Trotim is an example of a person who is mad.
But an example I'd reach for first is ctf_wildfire. It won a contest, got played a bunch, and from what I could tell lots of people liked it and it was a lot of fun. But now that we've had a good chance to mope some more about CTF, we're not playing it much at all. Why?
I don't because I never liked it, and once both teams know the map it turns into stalemates/deathmatch
things wrong with ctf in tf2:
spies being able to reset intel (decloaking, DR spam)
intel return timer always resets to full and is usually too long
return timer doesn't go any faster when your team defends it/no instant return
intel crits. I mean seriously? let's have cp crits next so the team capping mid can steamroll to 2nd for free
heavies
engineers
and those are all just the game itself but keep in mind you also got brilliant maps such as ctf_2fort and ctf_well