Ok let me explain in greater deal so all the non mesmers can understand, and hopefully the devs can understand what has gone wrong here in clean concise terms; so cast aside your preconceptions about this being a DPS arguement or just mesmers whining.
Class mechanic resource
All classes have a resource that is associated with their class mechanic. Rangers have a pet they double team with and the pet is traited and controleld to further boost the effectiveness of the pair, warrior build adrenaline and there are traits that give additional benefits such as high defence when adrenaline is high. Thieves are based on initiative and their traits and skills revolve heavily around it.
Mesmer’s class abilities use illusions as their resource. Mesmers are semi unique (along with rangers) in that their “resource” can be directly attacked by an opponent to deny them access to it. The problem with the nerfs is that now not only can you destroy teh resource, but you can deny the mesmer even generating it, simply by having aegis up or blinding them.
Phantasms as attacks, not pets
The next thing is the common misconception of phantasms being “pets”. Mesmers do not summon illusions like minions, they are an exotic single target attack, they deal damage comparable to any other classes heavy hitting primary attack and most mesmers don’t expect a phantasm to live long enough to hit twice, to all intents and purposes a phantasm is foremost an attack and secondly it generates a point of their class resource to then convert into a shatter or defensive ability.
When a warrior drops his hundreds blades, or a thief drops unload blind or aegis only blocks the first hit. But when a mesmer uses a multi-hit phantasm, say iWarden or iZerker, if he is blinded all the damage from the phantasm is mitigated and he also loses his class resource. it’s like blind stopping an entire HB barrage and then killing his adrenaline.
Not only this, but the failed attack goes onto a full cooldown cycle afterward!
Illusions as utilities
Not all illusion spells are offensive. iWarden can be traited to behave as a missile shield, iDefender provides AoE damage mitigation, iDisenchanter provides anti-boon/anti-condition support.
However since these require a target to be summoned, blinds and blocks prevent the mesmer using an on self utility spell (imagine thieves reaction if they wern’t allowed to use shadow refuge while blinded xD). Furthermore many illusions can be traited to provide additional benefits to the mesmer like regeneration and protection when in close proximity, in much the same way engineers can be traited for regen and swiftness while using a kit, again these on-self traits can be blocked with obscure things like blind, block or even a dodge roll.
Very unpredictable.
In summary
The nerfs however well intentioned have ended up being farther reaching than I think arenanet intended. Mesmers are punished to an extreme degree by conditions that do not affect any other class nearly as harshly; to compare it to another classes mechanics, it’d be like making a warrior lose all adrenaline, and completely interuppt his entire next skill, (even if it was a multi-strike skill like HB), AND deny him the ability to use his warbanners simply because his current target has aegis up.
My suggestion
Make blind/block/daze/dodge etc affect both mesmer and phantasms. If the mesmer is blinded, his phantasms are blinded; in the same way a ranger blinded can’t shoot you, a mesmer blinded can’t “shoot” you with his illusory ranged attacks, while at the same time not taking away their ability to build resource points or cast utilities
