Type 23 is ancient. We have, or will have type-26 Global Combat Ship. http://www.royalnavy.mod.uk/the-equipment/ships/future-ships/type-26
The Navy has been researching laser/energy weapons and rail guns…I’m pretty confident that it’s not an insoluble problem, and this leaves aside conventional countermeasures.
As for bullets, well, there are bullet resistant armors available that can stop up to 6 AK-47 rounds to the chest or back, so, while not proof against all bullets and while they have downsides (such as weight) they at least mitigate the risk. And, of course, you can always further mitigate the risk of a bullet by other means, such as killing the shooter long before they get to take the shot.
The point of all of this is that for every attack there is a counter, and subs or sooper dooper missiles or torpedoes aren’t the be all and end all, rendering everything else obsolete. Surface combatants aren’t obsolete nor for sure dead meat in a modern engagement.
Could you repeat these arguments? BBs and carriers are both expensive, there’s that.
The main reason BBs were replaced by carriers is because carriers are able to indirectly detect and engage at much greater distances than BBs while taking less of a risk.
What systems will be best able to reconnoiter lots of area to detect those radar signatures, rush in to launch their weapons and then eggress?
And you could put someone’s eye out.
What you’d probably end up with would be something in stages; first, I imagine that one side or the other would attack, and the other side’s CAP fighters would intercept. The escorts would engage with AA missiles (Standard SM-6) at any ones that got past the CAP, and at any missiles that they may launch at the battlegroup. Finally, the RAM and Phalanx systems would try to engage any final stragglers making it past the larger AAM systems.
Lather, rinse, repeat until one or both sides is disabled, or when neither side can mount any effective air strikes. It’s unlikely that the escorts would peel off and try to close inside the 70 nm range of the Harpoon missiles; that would be leaving the carriers undefended.
Carriers are NOT just for rattling sabers; they’re the premier anti-ship weapon platform in navies today. They happen to be versatile enough to bomb land targets, but historically, they’re what supplanted the battleship as the primary capital ships of modern day navies.
Nonetheless, they are excellent for gunboat diplomacy, what with nukes and such. 
Someone will if I don’t; ARA General Belgrano wasn’t a “battleship.”
HMS Conqueror, which sank it, was and remains the only nuclear submarine to ever destroy an enemy vessel.
Well, that’s a bit artificially limiting; most navies operate diesel-electric submarines. It’s really only a select few that can afford nuclear subs.
Indeed. Former USS Phoenix, CL-46. Brooklyn-class light cruiser. Launched and commissioned before World War II, so quite geriatric by the time it hove into Conqueror’s periscope.
Here’s a sampling:
http://sploid.gizmodo.com/are-the-us-navy-supercarriers-useless-1484497670
And then there was the Chinese sub that managed to embarrass the Navy several years ago.
http://www.washingtontimes.com/news/2006/nov/13/20061113-121539-3317r/?page=all
Diesel electric submarines are cheaper and often quieter than nuclear ones. Do a google search, submarine wins naval war game. Several instances pop up about subs taking out carriers. A nice video about an Australian sub sneaking up on U.S. ships, who were purposely looking for it in a small area. Also a U.S. nuclear sub was in on the hunt. Carrier groups have been defeated many times.
There’s a big difference between the willingness to sacrifice ships in a full on war for national survival versus risking them in the kinds of minor wars we’ve been doing since 1945.
There’s no doubt modern warfare will be real lethal. It won’t take too many shots to kill a whatever, be it a ship, a city, or a fixed ground installation. The countervailing feature is that nobody has all that many shots. There’s still plenty of dumb bombs, dumb artillery shells, and dumb bullets. But for the high lethality smarter or more potent weapons the magazines are real shallow.
It might easily be the case that both sides lose half their fleet in the first 24 hours. Then the surviving fleets, now devoid of ammunition, retreat impotently to their respective harbors. Subs too, having shot all their torpedos. Sadly, both sides’ munitions factories only put out a handful of new missiles of type XYZ per month. So neither side can quickly rearm for another war-spasm.
This is where nukes get into the picture. They contribute to stability up until the conventional shooting starts. But once two nuclear-armed states are doing serious conventional damage to one another (or even just to their expeditionary military forces), the odds on somebody reaching for their nuclear forces as a reinforcing tactic is IMO all but guaranteed.
The only way to win is to be smart enough not to play. It’s far from clear to me that all nuclear powers share this attitude. In fact one can marshal a pretty big pile of evidence that they don’t.
Sleep tight, World. Probably nothing will happen overnight. Probably.
MAD has worked for quite a while. 
Would MAD work with more than two players? Could, say, China just wait for the US and Russia to duke it out, and then sweep in to collect the spoils?
It works better in that case, there’s less incentive for the US and Russia to duke it out. The problem comes when two of the players join up. Luckily the US can beat the snot out of the rest of the world’s militaries combined right now. Luckily I’ll already be dead when that is no longer the case.
Google Close-in weapon system or Sea Wiz. Poor missiles don’t have a chance.
Those systems aren’t perfect. The simplest way to defeat one is probably to concentrate fire on a single warship, because you have an imbalance in that CWIS is short range while offensive missiles are very long range. So you can attack a warship along a firing arc where only 1-2 CWIS turrets can hit the missile and where a limited number of neighboring warships can support, while dozens and dozens of missiles can come that direction. The missiles are on the order of a million bucks apiece, the warships they kill are on the order of a billion, (and the missiles are a disposable weapon while the warships require you to train new crew to replace one) so this is a profitable trade.
What naval and air weapon systems are most effective in terms of cost, ease of production/training and effectiveness (aside from the ones I’m about to suggest)?
A middle ground has been developing between 2000$ dumb bombs and 1 000 000$ missiles.
Pretty much everyone here will know of JDAMs which cost about 25K$.
The APKWS II costs 28K$ with a range of 5km which could increase to 14km with a longer rocket.
A SDB costs about 40K. The ground-launched version could be launched from ships and its 150km range would be pretty good.
Cite (among others) Rockets galore
Advanced Precision Kill Weapon System - Wikipedia
GBU-39 Small Diameter Bomb - Wikipedia
Would any of those be candidates for ramped up production sufficient to prosecute a war?
In addition to what Habeed said, those weapons use radar to aim. IR would suck at estimating range and velocity. Anytime something uses radar, you can mess with it. Incoming missiles only need to keep messing with the CIWS’ range and velocity gates for less than 15 seconds to go from a CIWS’ 4km max range to the target ship. Not a trivial feat but also far from not having a chance.
Like the IRA told Maggie: “we only have to be lucky once – you will have to be lucky always.”
If a ship wants more range to its anti-missile defenses, it’ll have to use anti-missile missiles which cost as much per unit as the missiles they defend against.
Harpoon (missile) - Wikipedia (1.2M$)
RIM-116 Rolling Airframe Missile - Wikipedia (1M$)
RIM-162 ESSM - Wikipedia (1.4M$)
ECM though, tends to have much lower cost per use.
I know I’m being a tiresome cunt with EW but it really is central to naval and air warfare.
Compared to those tin cans the Brits were using, that thing was a battleship. As well, it was not put down by a modern torpedo, at least modern then. But by a WW2 contact torpedo.
Declan
Exactly how many navies do you believe exist with that many missiles in the magazines, combined with a bomber fleet of some sort, and fast attack subs to round out the engagement. I think 12 is the latest number of navies that can mount that sort of attack to some degree. Co-ordination between the services, you have to start playing the odds, regarding the overall success.
Basically thats called a first strike, otherwise, your hoping for tactical surprise, as you have already squandered strategic surprise. So, other than playing harpoon on our pc’s and having a grand ole time, what political event kicks this off, that someone would have to be insane enough to think that he or she could sortie their entire fleet, put their air launched anti shipping on alert, find a convienent enemy and Weber them.
You would have to game the Russian V Chinese navies, cause I am not seeing the above with the entirety of the USN surface fleet at one time. Usually the American approach has been to kill the archer, not the arrow, Almost everything you have posted is a last ditch measure, even the sea wiz has been replaced by ram missiles. Add the bloomers, to take one for the carriers and troop carriers, your still looking at what remaining ships you have, being sunk in port when the return to refuel.
Declan