Closing accounts is really not complicated at all. Opening one can be a bit of a pain (unless you go the all online option, which I would avoid), but if you wait for a good enough promo it is worth it. I think we made something like $300-$500 off of Chase, but it required keeping a $16k balance in a savings account for like 6-12 months or something like that. We would have got like $100-$150 just for opening the account.
Also, if you currently have separate accounts and you are worried about it being a PITA to open a joint account, then at least you could think of it as avoiding the hassle of one of you dying and then having to get access to the balance through other channels.