Telrath the Disruptor

I think that Telrath's Destroy Shields could stand to be buffed a little bit. It's max damage (to only your shields) is 220 damage at level 4.
Then I played with Grove Guardian and he has Nature's Wrath which deals 320 damage at level 4 to multiple targets. (I think 4 targets is the max I've seen it do even though its a cone attack)

Destroy Shields - Combusts 55/110/165/220 mana from an enemy unit. The destroyed mana deals an equal amount of damage to the unit. Cooldown: 22 seconds.

Nature's Wrath - Deals 80/160/240/320 damage to units in a cone around the target unit. Cooldown: 20 seconds.

Here are a few notable pieces of information you're missing.

1. Telrath's Destroy Shields actually only burns 200 mana in b2.4, not 220.
2. The burned mana combusts, dealing damage equal to the mana burned. This means that it's actually a 400 damage nuke if they have 200+ shields to burn.
3. Telrath is being remade in b3.

One more notable thing:

banish + mana burn = 1.33 * 400 dmg = 532 damage (yes cuts through HP)

Combo that with his ulti and now an 'underpowered' hero is suddenly 'overpowered'

Hence the remake.

Also because Suave is rly mad that I dodge all his Mana Burns. <3

That combo is brutal as it is, but pair that with a strength hero like Minotaur and you got all kinds of silliness.