now first off i am in no way a huge player of PvP or TB but i have been reading about it's problems.
my attempt at a soulution may or may not work but i thought i'd just put it how to see what people think
maybe if a system was implemented so that instead of the number of people around a tower counting towards the capping of the tower: how about a kill/death ratio.
example: horde hold the north tower - they get a kill/death ratio of let's say...15.
so the alliance attempt to take that tower, they kill an orc warrior (example) the k/d changes to 14.
a gnome mage is then killed. the k/d goes back to 15.
the alliance would contol the tower when the k/d ratio hits -1, then the alliance would recieve an automatic 15 k/d ratio on that tower
the numbers are just an estimate but i think you should get the general idea.