I'd enjoy Territory Control if it was just easier to attack.
CTF can get rather boring, since it requires a lot of effort to get the flag in the first place (nothing like UT2004 or whatever where it was pretty easy give or take to do this).
CP maps are my favourite really I guess, Payload is okay too, but some of the maps have very difficult points to capture (but Badwater Basin is a nice map for any class, and being one area is great!). I like CP_Steel as my favourite attack/defence one, since it requires people to think about more then one point and avenue of attack, and alieviates the "choke point of death" problem that Dustbowl and so forth have.
However, Well is crap. I hate well for various reasons. I still don't know why Valve like it so much. Even Granary is better then it.
Arena is also bad because of the respawn time. I'm not playing Counter Strike for a reason, and that reason is utter boredom when dead. Also; you spelt the prefix wrongly, since Valve use "arena_" as their prefix.
I'd not mind some new gametypes. I did quite like the old Hunted gametype, although it required a good hunted civilian

and wouldn't be balanced with the TF2 class changes now. The other ideas like a "centre intel" for a change to capture the flag might be nice.