As mentioned above, mine’s hidden, but it uses two passwords glued together from a password generator into the longest string the thing would accept.
Even so, I use an Ethernet connection with the desktop machine, and wi-fi only with the iPad, and I don’t use the iPad at any sensitive site, such as the bank.
Still doesn’t help.
The problem is if you ever take your iPad out of the house and attempt to use it with WiFi (say in a café). So long as the iPad thinks that it needs to ask for your home WiFi network by name, it will ask for it, wherever it goes. So in the café, your iPad will ask for your home network, the black hat’s base station replies with the name, and the iPad then sends the password. Bingo, you now have a man in the middle attack. Plus, if the black hat so desired, he could drive by your house, and now has the needed password to use your home network.
So, with a more targeted attack, if you had really annoyed someone (ex-spouse, work partner, some other reason to hold a serious grudge) you are open to all the sorts of malicious attacks someone who wanted to cause you harm could mount with access to your home WiFi. Your home WiFi is essentially as secure as if it had no password at all. It matters not one bit how long and difficult your password is, so long as your iPad treats the base station as hidden, it can be trivially coaxed into revealing the password.