Towers are not too strong, but a tower full of enemies in your homeland shooting your women after you've just lost most of your troops repelling their invasion is too strong. 

A tower cost 200 resources, same as 2 infantry, we'll take account build time and say 3 infantry... Considering this, you can see why building a tower SHOULDNT be too strong as to for the enemy spend excessive time to take it out. When the building balance is making buildings too strong, then game stalls and it's boring. Which is why this alpha (a27) is refreshing because building are balanced. We can make the same comparison we did with towers with other buildings like CC and forts both as costly as 9 infantry. Yet a CC even being easier to capture now can score 80 kills as I often witness in games, and forts even more (100 not being uncommon even saw 169 once).  The towers enemy capture in your own territory, decay 10 capture point/sec iirc, so recapturing them is actually much more at the advantage of the original owner. Next alpha, CC and forts will be back at being almost impossible to capture, which I regret because it will close strategic options, forcing players to always go for rams, even when you only need to defeat a naked CC. But I guess the majority of people think that's how it should be..

Yes I like capturing in general, it's just that the difficulty of doing it needs to be proportional to the amount of harm it does.

But it is a nice strategic element in decimating a powerful opponent  Also useful is capturing a temple and heal your units, or capture barracks and locally train more forces without the need for long haul troup transport.

The main building I want less capturable is the tower. It's too easy to take a tower in enemy territory and fill it up with units, and too hard to prevent that.