Here is some suggestions for skill balance from me with reason.

Puck - Reduce Illusory Ord travel distance.
(Shot from long distance and high gamage.)

Ursa - Enrage remove ''can be use while disable/stun'' or damage reduce from 80% to 40%.
(Can't do anything when he get the aghm upgrade and BladeMail.)

Doom - Doom silence duration reduce.
(Long Duration and stun from Neutral skill.)

Mirana - Sacred Arrow reduce stun duration or travel distance.
(Shot from long distance and long stun duration.)

Disruptor - reduce duration of Kinetic Field or Static Storm.
(Get caught and ready to die.)

Bristleback - Damage per stack reduce or 0.4 sec cast delay.
(Get Roshan in 10sec after game start and high stack damage Quill Spray.)

Earth Shaker - Reduce Fissure attack range.
(Long range with stun.)

Faceless Void - Cronosphere only last 1-2 sec.
(Trap enemy or teammate for kill with spamming cronosphere, usually last 10-20sec.)

Dragon Knight - Breath Fire with cast delay or reduce damage.
(2-3 casts per sec and high damage.)

Shadow Shaman - Serpent Ward Damage reduce 60% or recude duration.
(High damage and long duration to spam 8 times. 8x10 wards= 80wards.)

Bounty Hunter and Nyx Assasin - Invisible duration recude to 5 sec.
(Long invisible duration with stun skill, only can be counter with Dust ,Sentry wards or Gem, waste gold on Dust and sentry wards. If they get the gem sentry wards will be useless.)

So what do you guys think, is it too much?