As implied, this will contain SPOILERS, so read at your discretion, and if you contribute please
your responses!
Surely you've seen a show that either had a really crappy ending and could have been better or a good ending that could have been great, with that. I shall start:
Last Exile: Last episode should have been two, could have put more valuable things in there which could have made a bit more sense
Clannad: In my opinion
a kissing scene with Nagisa and Tomoya would have been great, it was really well done in Kanon, and Key could have done better ten fold with Clannad, hell, at least HOLD HANDS, YOU WON'T GET PREGNANT!!! (not until ~AS~ anyway...)
Clannad ~AS~
I was thinking one day amidst the rat shit and shoveling, I thought that ~AS~ could have taken another route with Tomoya falling for Kyou would have been an interesting turn, but I think I would have swallowed rat poison, jump off a roof and land on my hauntavirus infected shovel, main point being to this, they could have at least shown Nagisa's face a few times, and instead of a "compilation" episode, call me tacky and cliche, but some form of marriage or reunion scene, would have made a great ending end even better.
Kanon:
Could have been a bit less vague about Yuichis miracles, some explanation would have been nice, great one still.
Valkyria Chronicles (yes I watched it, was ok, save the love BS triangle):
he was a douche all through the anime, then he does something cool at the end, kinda felt bad for him after I laughed a few times...
P.S. They lace Taiyaki with COCAINE