[...] which i've never played [...]
And this little text snippet makes everything else you wrote in your post pretty much meaningless.
(If you do play the map just to confirm your "theory" your opinion will still be useless since now we know that you approached it in a very biased way before even seeing it.)
Junction is OK, by the way and its ratings and popularity on FPSBanana speak for themselves. I'm not saying that there weren't better options but hey, at least many custom map fans won't have to adapt since they are familiar with this addition. TF2 doesn't have a map that is 100% indoor yet and there are still some good sniper spots on junction, which everybody who actually played it and doesn't merely fantasize about it would know. =)
Watchtower is pretty irrelevant since nobody will be playing arena mode on our servers - there were better custom map choices IMHO but then again we get a very open map for a change.
Not really because the sentence he quoted says it all, it is exactly that, a massive orgy of spam. Its pretty much a smaller version of steel with a ridiculous last point which is easy to defend if your team aren't complete idiots. The last point is actually going to be impossible, since they will definitely have sentries on it, the sentries can only really be taken down by 1-3 demo ubers, depending on how well placed they are (1 demo uber would be lucky), but 2 pyros with compression blast will completely nerf the attacking team. Or even a scout decent with the new baseball weapon.
If you are half decent at aiming with rockets/pipes the map is a piece of cake, until you get to the last cap where there is mostly just a sentry + demoman spam. I have played this map a lot and this is what it tends to be like, especially on large servers. Its the easiest map to rocket juggle people since they get blasted into walls/ceilings all the time. The corners make it easy to sticky camp and pipe anyone who gets through. Heavies + Medics rule on it though, unless they have well organised spam then you will be obliterated by the demos + soldiers
@MikeDH - There is no way you will be able to scout on Junction, unless your objective while playing scout is getting sticky camped and hit by 40 rockets at once, or even just meeting heavies in corridoors. Sniper are pretty much useless until you get to the last cap, where if you are defending you will do alright, but if your attacking you will probably find it hard with all the spam. The multiple routes are only accessable once you have taken one of the first points unless you are lucky that the defenders are distracted by one point, even if you do access the route you will more than likely be killed due to the size of the map.