As a player of spellbreaker and a player of 6 other classes I will confidently say that the sustain and the mechanics on spellbreaker are balanced. The fact of the matter is that spellbreaker as it stands now has many opportunities for outplaying and it is exceedingly easy to bait out/waste the cooldowns of a spellbreaker. As a multiclasser, I can beat spellbreaker easily on ranger, ele, core guardian, and revenant. When it comes to balance, this is the ideal scenario, where a class can be beaten by 4 other classes yet can beat the rest. A spellbreaker is mediocre in winning 1v1s after the various nerfs making it necessary for it to run rousing resilience and rampage. It performs its best in stalling a fight or sustaining in outnumbered scenarios due to the low likelihood of both enemies playing optimally to bait cooldowns as a duo and not CC or proc full counter. The full counter mechanic does NOT need a nerf or an increased cooldown. It's truly fine the way it is.