For a game as strategic as TD, the timer is way too short. Great games just end early with one side winning because they spammed creepers 5 minutes in. In my opinion, there should be a boss bar that represents the time, showing the time before Armageddon at the half-way point. Armageddon should start 45 minutes in (with the Wither being buffed to compensate, of course) with the game lasting 30 minutes after this point. This would fix 2 problems; the short duration of the game and the inability to predict when the game will end, leading to losses simply due to the fact that mobs are too slow.
