You are almost right here. Mesmers and guardians don’t need massive nerfs. The problem is phantasms and retaliation.
The thing I’m seeing now is a mesmer in a phantasm build will spawn two phantasms from behind LOS to attack you (these days, greatsword and sword/pistol are used). If you are glass like the mesmer is, then half your health will instantly be gone because a phantasm is initially invisible to you when they are performing their first attack making it impossible to dodge. After this, all the mesmer has to do is stealth and hide behind LOS while summoning more phantasms. If the mesmer sees that you are far enough away from him or are attacking his phantasms, he will sit at max range attacking you with his greatsword until you target him again. Then he’ll just LOS, stealth and/or run away from you while re-summoning phantasms.
Ok, here’s an informed opinion, but not quite in the full of the scope.
There’s a reason why cheap mesmers like the one’s you describe are using Pistol/Greatsword, and it has very much to do with line of sight, or more importantly, pathing.
The only two Phantasems that can completely bypass line of sight is Berserker, who spawns in direct association to the target (Regardless of line of sight) and Warden, who obeys the same rules, but is rooted.
Duelist attacks at range, but spawns in relation to the caster. They have to run to you and hope they get in range before reaching Mesmer’s max illusion range (in which case they shut shatter regardless of cooldown.) This function is shared by every other Phantasem type.
The player who’s allowing themselves to be assaulted at range is doing a poor job persuing his targets. Get a roamer to push him out of his max range for his phantasems and he’s not a threat. That, or blanket AoE’s where you’re bunkering and keep an eye on where the duelists are spawning.
As far as adjustments in this vein. I’d be ok for a Line-of-sight requirement on iBeserker, so long as misfiring my illusions puts them on a shorter cooldown. Suffering the full cooldown because some sniping ranger of thief decided to duck behind a rock would be infuriating and class crippling.
iSwordsman and Duelist should be fire-able regardless of line of sight as it has to move to its target, and again, Mesmers have a limited control and summon range on all illusions. As far as adjusting these two in terms of damage, that’s going to be more trickey as we have several things factoring in on why they’re doing so much, and each individual reason is fair. Though, how about trading of one of the Illusion/Phantasm damage traits? We don’t need both as Illusions are kind of pointless damage wise. Either one of these traits can be changed into something different, and there’s your damage nerf.
As far as Mesmer’s elusiveness, THAT’s a learn to play issue. Again, most phantasms originate from a mesmer, so if you’re seeing phantasms walk around the corner towards you, go around the corner. I’d eat a larger cool-down for our blink (not phase retreat, blink.) considering it’s a stun-break + relocate, but I’d like to have a trade off for it.
