I have reasonably keen senses, though I do whomp my head, arms, and legs into things, so I voted for that as my weakest sense. It’s more about lack of focus, though.
You don’t want a bloodhound nose. It’s a curse in so many ways.
I said balance but maybe the propria whatever it was is more accurate. I have a learning disability that affects this so it is a matter of just how it is, I don’t really notice because I have known any difference. I learned some copy mechanisms many years ago. Balance however is another matter, I used to be quite agile, I remember “rock-hopping” on rivers and streams in the Smokey mountains and easily jumping from rock to rock, I recently went to Coronado island and wanted to look at a tide pool in some rocks and I could hardly step around. I got old somewhere along the way. 
Probably my sense of taste. I love cooking and eating good food, but the gourmet notion of a subtle pallet of flavors, “rosemary with just a hint of citrus ending on a note of anise,” is totally lost on me. Maybe too much spicy New Mexican cuisine in my youth has done me in.
Curse you for beating me out on my #1 choice! 
Even my #2 choice – “fashion” – is taken!
Direction. Seriously, I have trouble orienting myself in a strange town, or even in the town in which I’m living.
At least I have an extraordinary sense of smell. For the five normal senses, my hearing is getting poorer as I age. All that work around heavy equipment and runways took a toll.
Oh the hell yes. I get lost going to places I’ve already been to several times; I’ve taken wrong turns on routes I’ve taken hundreds of times. And forget it if I’ve never been there before. I’ve even gotten lost while using both a map and GPS!
Vision. It’s not even close. Without my glasses I can barely read the clock on the other side of the room, 10-15 feet from me.
Hearing, for sure. After years spent in data centers, my hearing is shot and I have a constant ringing in my ears that never goes away. The disorientation makes it really hard for me to be in crowed, noisy places, and I have a hard time hearing anything in a restaurant.
Have you ever read Midnight’s Children or Perfume? They’re both interesting - though very unscientific - ways of looking at what it would be like to have a heightened sense of smell compared to other humans.
Smell is also terrible for me but TBH I consider that an advantage. For one thing, it might have helped me keep my weight down - I’ve never been a foodie and that might be partly because I don’t seem to smell or taste things as much as other people do.
I voted pain because mine is messed up. Doesn’t sense some stuff it should, over-senses stuff it shouldn’t.
My eyesight is crap but lenses correct that, so I don’t count it. Also other aspects of sight, like the kind of visual perception you use for Where’s Wally/Waldo (he’s Wally in the UK) are fine or good.
The others are all pretty good - great sense of balance, hearing is good, virtually no cocktail party effects - so I don’t think I’m doing too badly overall, really.
I taste some smells. It goes along with the fact that I smell a lot of perfumes and the like as rank mixes of chemicals; when that happens I taste them too. It quite literally feels like the airborne chemical particles are settling on my tongue.
It’s not pleasant.
Smell is a funny thing. Dogs of course have an amazingly sensitive sense of smell, yet my dog once happily bounded into the house soaked from head to paw in La Essence de Skunke, and it didn’t seem to bother him one bit even though the intensity of the stench was threatening to cause the paint to start peeling off the walls. I think the moral of the story is that dogs are incredibly easygoing and laid-back. 
Probably vision. I got LASIK 15 years or so ago and it improved from seeing nearly nothing to seeing nearly everything, like a superpower. But age has started to deteriorate it again, and now it’s at about 70% what it was post-treatment. That’s still way better than it was before, but as far as I can tell all my other senses are operating under normal parameters, so vision is still the lesser.
I have started to get a bit dizzy lately, coupled with that weird “migraine aura” visual effect (but without any headache) but I don’t think that’s anything to worry about, it seems to be a very common issue.
I am also a supertaster, so that means my sense of taste is very sensitive and some things that other folk would find mild or pleasant, I instead find too strong or entirely unpalatable. But technically that’s a sense strength, not a weakness.
I’m another whose answer is “smell” – the one with the most votes at present, I notice. I have a sense of smell, but it’s weak, and misses a lot of things. No particular cause – I’ve been so from birth, as far as I know.
A blessing at times, indeed. A late uncle of mine was like me, in having lifelong, a poor sense of smell. His wife had a very acute sense of smell; he remarked often that he was profoundly grateful to the Almighty, or nature, for his weak s. of s. – his spouse was forever encountering bad smells and suffering accordingly, and as he said, “it makes her life a misery”.
ESP
(Which might be what ikeWitt was implying in post #34, but it’s ambiguous)
Spidey - worst
Non - best
Clairvoyance. Honestly, it’s so weak that I might as well not have any at all.
FWIW, it’s a sense you can improve tremendously with practice, if you care to. Most of it is trying to figure out what you’re smelling, and distinguishing it from other things you’re smelling or that you’ve smelled. Books on wine appreciation are a good place to start.
For me, I don’t process auditorily very well; I hear you, I just don’t often understand you, or take what you’re telling me and remember it a few minutes later. Same with sensing time; I can do it, if I’m concentrating on the time elapsing. Ask me to remember to do something in 20 minutes, and I’m hopeless without a set timer.
Anymore; hearing, especially higher frequencies. I get by most of the time. The only people who tell me to get a hearing aid are soft/softer spoken women in situations with some background noise.