In my opinion, and I've looked at TC a lot, the best start at going about fixing TC, would be to use Koth.
You want to not use choke points, or corridors, like all TC (Custom and Hydro) have atm, you want Yards. And to prevent one team from turtleing you want an objective that forces offensive play.
So it would be in my opinion that the best TC map, with be one that uses the KoTH mechanic, rather than the 2CP A/D mechanic, and has "yards" (much like a koth map) rather than corridors.