Part of the problem is that Infinityward is patching the ways that people use to get to a "glitch" rather than the spot itself. Take for instance the Helicopter in Bakaara. They patched the method of getting up there using the tail of the helicopter... but then people just jumped out the window. And now the only way of killing them was the same way, through the window. It made it super easy to camp the helicopter blades. They did eventually patch it the rest of the way, but the piont still stands.
So that's #1) Patch the spots, not the routes. There are always alternative methods up.
#2) Remove Split Screeners from Infected. I've come to believe that unfortunately, that's the only way you're going to stop a lot of the boosting where someone blocks the only entrance to a room with their split-screen counter part, and then has the player get easy MOABs out of it.
#3) Remove the MOAB. In it's place, make it so that if you manage to get 25 Kills, you get double health for 1 minute as a bonus. It's not enough that will make a huge difference (2 knife hits = dead), but gives someone that fighting chance to make a stand and survive, especially if they do patch all the main spots people hold up. This one is of course debateable, and may not be favored by many... but I thought it might be a nice little bonus in place of the MOAB.
I like your third suggestion I think it would be a fair replacement for the moab and would not change the game too much.
I an agree something needs to be done with the splitscreen issue allowing boosting. But if the stats were no longer tracked boosting would be pointless except for exp gains. Which is where exp gain was removed, boosting would be pointless period. No stats, no exp game mode played for fun only.
Your right on they need to fix the spots themself, but by fixing the routes they got to learn of other ways to get there. I find it funny that they needed this game mode to teach them where their bounding boxes had issues about where people could and could not go in the game. Just shows that a sem-open beta may have helped.
I can agree witht the need of more weapons but the chosing of them would need to be carefully done. Give the survivors too easy of weapons to use and the infected will just quit out and rejoin all the time and matches would only ever end up being survivor wins again like when the TK was removed and a map like dome came up.