1) Why do competitive players dislike current stock CTF maps?
a) What makes 2fort awful?
b) Why is turbine sometimes acceptable, but barely so?
2) Are the problems with the maps, or with the mode's mechanics?
a) Are there any adjustments to the way intelligence is picked up, returned, and/or captured that can improve gameflow for 6vs6?
b) How will any potential design changes impact the usefulness and overall power of individual classes?
3) Should maps be designed exclusively for 6vs6 play, or is it possible to reach a globally accessible design that scales well from 12 to 32 players?
1) I can't say with certainty, as I don't play competitively, but going off my own CTF experience, I'd say that they dislike their tendency to stalemate. Furthermore, the scoring system encourages turtling the instant you fall behind to prevent further captures. The competitive scoring system means that if you fall behind, you
have to attack. Given that competitive players like fast-paced gameplay, this suddenly makes a lot more sense than it did when I started typing this paragraph.
a) There are a lot of things wrong with 2Fort. For starters, it's possible for a single Sentry to lock down all possible paths to the intelligence. For that matter, there aren't enough paths to the intelligence to begin with. Everyone is funneled through the same room (the courtyard), which means that every Engineer and their mother has a Sentry set up there because they
know you'll have to face them eventually. (Interestingly, the core competitive classes can all bypass the courtyard because they all have extra movement abilities. Well, except the Medic.) And once you do get the intelligence, it's sufficiently deep within the base that you have to battle your way past a freshly spawned wave of enemies. This is not helped by the fact that you have to pass within spitting distance of the spawn room on your way out. (And in, for that matter.)
b) Turbine is probably tolerated because it avoids a lot of the 2Fort issues. The bases are not so huge as to bury the intelligence within, there are 3 distinct routes to the intelligence, none of which converge until you're in the intelligence room itself, and you are not forced to go anywhere near the enemy spawn room. However, it creates some issues of its own. First, all possible exits from your base are on the same wall, which makes it easy to lock down the middle area and trap you in your own base. Second, out of the 3 paths to the intelligence, one goes right past the enemy spawn room, while the vents tend to be a deathtrap. (In my experience, anyway. Recall my disclaimer that I don't play competitively.) This leaves only one regularly viable path to the intelligence, which once again creates predictability in the attackers and makes the defenders' job easier.
2) I'm pretty sure this was implied in the way I was talking about it, but I believe that these are problems with the maps, not the game mode. Doublecross is a CTF map with easily accessible alternate paths and several one way entrances and exits in close proximity to the intelligence. It still has a spawn room annoyingly close to the main path through the base and it's still possible to make life hell for any intelligence carriers by building a Sentry on the shack near that catwalk, but the sheer number of ways into the base and that delicious one way drop next to the intelligence room means that it's quite difficult to keep the enemy from getting your intelligence, which shifts the gameplay towards keeping them from getting away with it. This is in contrast to 2Fort/Turbine, where teams tend to focus on keeping the enemy out, and where the side paths are not worth the extra cost or risk involved.
a) I believe the most fun part of CTF is the period where the intelligence has been dropped and both teams are in a rush to get it back before the timer ends or defend it for that time. The relatively long return timer and the resetting of this timer both help extend this period. This is one of the reasons I'm shakey on a touch return on the intelligence -- there would be no chance to recover dropped intelligence unless you were already in your base, so it would just be the same old grind again. One change I'd be interested in experimenting with would be a stipulation that your own intelligence cannot be anywhere but its starting location before you can capture the enemy's, but I have absolutely no idea what ramifications that would have for overall gameplay and balance.
b) Reducing the timer on dropped intelligence would give less incentive for Engineers to set up impromptu Sentries to cover it. (Whether this is good or bad is open to debate.) My personal reservations aside, touch return could give additional utility to Spies in the enemy base who could backstab the carrier and touch their own intelligence. Compare this to now where intelligence in the enemy base is as good as captured unless you have an epic spawncamp going. Requiring the intelligence to be "home" before capturing the enemy's...again, I don't know how that would play out. It could create an interesting dynamic with touch return though, where you need to seek out an enemy flag carrier in your base and return your own intelligence before you can capture theirs.
3) Should maps be designed exclusively for 6v6? No. Is it possible to make one that both competitive and pub players will enjoy? Yes, but it will doubtless take a huge amount of time and plenty of iterations.
Phew, that was a wall of text...but it helped me think some more about the contest and what I could do, so I'm glad for that.