Gpit isn't better than any map we're currently playing regardless of whitelist.
It was removed partly because its an even more undesirable "chore" than viaduct is for it being the only map on that game type, on top of that being A/D in particular.
Which brings me to the other part of A/D at the top level consisting of either constant suicide plays into a heavy/engi to get a force (which some lucky player gets to play for half the game), or sitting on your sniper for a minute or two until you can work him in far enough to get a kill, both with a giant height/positional disadvantage.
Watching it can be neat but playing it literally feels like trying to break into 5cp last uphill against a parked bus.
I'm all for testing things that can potentially improve our TF2 experience but gpit was removed for a reason and is a lost cause imo.