Well i think TB has much more potential in late game >= lvl 15 if he is skilled hybride
with the Rain of Ice he can easily kill most of the creeps (giants are nearly dead). The fireball is a nice spell to do high dmg 2 other demigods or to kill towers and his ice spells with their interrupt are really helpfull in late game.
Well lets talk about his dmg in late game:
Rain of Ice 800 (2 effects that can be consumed by Deep Freeze)
Frost Nova (nice stun and slow at demigods and creeps and 1 effect that can be consumed by Deep Freeze)
Deep Freeze 1275 (only on singel target with all 3 effects consumed, but it is an nice interrupt and the cooldown is increased by 220%)
Fire Ball 1350 (just a single target, maybe demigod or tower)
gz you just did 3425 dmg in 6 seconds on a single target, killed lot of creeps, damaged towers and slowed the giants that are still alive, i think TB has a lot of potential in late game.