Here are some things that could use a buff and the right things to nerf - according to the mesmer community.
This is pvp/wvw oriented.
Feel free to add yours suggestions or share your thoughts (mesmer only community tho, no "knowledgeable community" allowed )
Illusionary Reversion: this one was downright smiter's booned at 16/03/2017 and even become worse at the next nerf, could use a revert.
Wells: all of them except gravity and heal are useless, could use some rework or tweek, bigger radius or pulse the benefits or affect 10 people in wvw or something else.
Lower heal well cd.
Echo of Memory : increase the aoe of the phantasm attack.
Tides of Time: this is controversial, some people prefer it this way, I find it incredible clunky to use. Revert while making not possible to fire backwards, alternatively nerf every other skill on game that can be fired backwards, gives 1sec alacrity and 1sec quickness on each way.
Mirrors: Maintain the current funcionality and add the following, when foes pass through the mirror, the mirror breaks and deals damage, it adds counterplay to the mirrors while adding a mesmerish mindplay feature - "if I don't break the mirror the mesmer gains an evade, if I break it I'll get damaged but will null an evade".
Crystal Sands: rework into something, this is useless.
Mirage Advance: reduce the cast time, this being 3/4 not only is clunky to use it, doesn't allow any combo but also screams dodge me! There are similar skills on game that are instant. Edit: Alternatively put 1 or 2 seconds of quickness on it, so you can burst right after teleport.
Sand Through Glass: up the rollback range to 500 units, the mirror spawns at the end location or up the range 50 and maintain the mirror at the end, or reduce the cd.
Illusionary Ambush: take out the randomness or lower the cd or get some trait to reduce deceptions' cds
Jaunt: back to 3 ammo or reduce cd to 20 sec, remove confusion from the skill if needed, no one cares about the confusion on jaunt, consider upping the range a bit in trade take out the damage.
Elusive Mind: take out exhaustion, cleanse 2 condis or 1 condi and -20% deception cds, alternatively cleanse 2 condis and grants +33% mirage cloak uptime.
Increase ambush efficiency : doubles boons/conditions granted by ambush. Basically transfer the damage to mesmer himself. Alternatively Remove 1 Condition when creating a Mirage Mirror. Reduce the CD of Distortion by x seconds when gaining Mirage Cloak.
Self-Deception - Reduce cooldown on deceptions by 20%. Create a clone when deception is used.
Infinite Horizon: make IH baseline and a trait to compete with EM (changed), reason being ambushes are hard to balance with IH choice, they're either bad or good/op. WIth this you can nerf more approprietly ambushes.
Ambushes: reduce cast time on ambushes so they can fit inside or closer to the mirage cloak uptime. (.75 MC taked into account)
Merge Speed of Sands with Mirage Cloak, they're intrisically dependent, at the current time it feels like each one is half a trait. Come up with a new minor grandmaster.
Lingering Thoughts: reduce cast time so it can be covered by mirage cloak, alternatively move evade frame from axe 3 to axe 2
Imaginary Axes: 67% damage nerf is an overkill. Replace torments for longer bleeds to allow damage to ramp up as conditions should be .
Evasive Mirror - rework into something, currently this is trash.
Blinding Dissipation - since you want to bind traits to specifics Fs, buff this in some way, this is currently trash.
Critical Infusion: revert, let nomad's endurance stay nerfed if needed. Precision is used by power mirages not by condi, so will get power mesmer some survivality.
Confounding Suggestions: Convert Diversion's daze into stun, maintain the daze uptime, some icd - so chronos can't abuse it, this way MoD and sword ambush can no longer proc the stun, good power mesmers always use f3 to setup the burst anyway...Increase diversion ammo to 2.
Rending Shatter: Vulnerability is increased to 2 stacks and time is reduced to 4 seconds.
Mental Anguish: Revert March 27, 2018 changes.
Fencer's finesse: Let's compare it to Swindler's Equilibrium, Silent Scope, Forceful Greatsword, this trait is clearly missing, it needs to hit 10 times to have the full benefit while the comparisons are pure passive traits. New trait would look like +120 Ferocity/power/precision; +120 additional ferocity/power/precision if wielding a sword; recharge reduced 20%.
Shattered Concentration - 2 boons removed instead of 1 (due to clone production reduction.).
Furious interruption - 1 sec icd instead of 3 (split for PVE if there are problem with this.).
Restorative Mantras - make the heal dependant of the mantra cooldown time and activate on mantra use instead of cast.
Protected Phantasms - phantasms give mesmer aegis after they get destroyed.
Signet of Humility - Reduce cd, since all transformations were reduced to 90, doesn't make much sense that the counter is still 180.
Time Warp - Make a glamour cd reduction trait.
Mass Invisibility - rework the anti-synergy between MI and Master of manipulation trait. Reduce CD to 50, if elixir s is fine the way it is consider lower MI cd to lower 30's. Alternatively give 2 ammo mechanic.
Decoy - reduce CD
Mirror Images - spawn and randomly split position the clones like IA
Decoy : remove the cancel activation time effect. (Aka don't get rupt when you are doing something.)
Arcane Thievery : Reduce Aftercast
Portal Entre : Bring back 60 sec duration but add 30 sec CD if portal Exeunt is used. Alternatively: Reduce the Max number of allies going through to 3 or even 2 and revert the duration nerf.
Signet of Inspiration: This needs to be based on what boons the Mesmer has.
Master of Manipulation - switch places with Bountiful Disillusionmentt, - 20% less cd on manipulation skills and improve the the following way:
Mirror (heal):+2s reflect
Blink: Breaks enemy targeting.
Mimic: 50% reduced adjusted cooldown.
Arcane Thievery: becomes an ammo skill with 2 charges (20s cooldown per charge).
Illusion of Life: increased "alive" duration and provides some minor stat bonus (defensive or offensive).
Mass Invis: removes reveal and outward radial pulse also hits up to 5 targets with 2s reveal (stealth your allies while briefly revealing enemies).
Mind Stab - Remove 3 boons, does damage per boons removed.
Illusionary Wave - The damage it does is neglectful - Reduce cd, hit on 180 degrees, consider uping the base damage too.
Phantasmal Warlock : summon only one illusion instead of two. Balance then the alone phantasm.
Chaos Armor - clean one condi on activation.
Confusing Images - buff the condi damage.
Mind Slash, Mind Gash : add 1 more vulnerability stack.
Mind Spike : dispell 1 more boon. (get the 3rd chain in PvP is nearly impossible btw.)
Blurred Frenzy: reduce the number of attacks to 4 while mantaining the damage, same as pistol whip.
Illusionary Leap - Make clone invulnerable for 1 second before its could be killed. Clone has 2400 hp,too easy to kill before you can use swap which makes skill useless and unreliable.
Phantasmal Swordsman - another controversial one, some people like it this way, I find it useless, revert back to poke phantasm or attach an immobilise to the first hit. The phantasm bugs out on uneven terrain, needs a fix.
Temporal Curtain - remove the after cast as long as we are in a meta where many class have instant hard CC aoe or increase the wall duration to 6 sec.
Phantasmal Warden - can he not get killed himself by hitting a war with retaliation ? Increase damage coefficient and (increase phantasm HP or condensate the number of hits (while conserving the bubble duration.)).
Replace torment with bleeding, take into account the damage and uptime to make sure it's well traded, this will make the profession less oppressive, you can now kite without taking damage and bleeding is overall easier to cleanse.
Mirage Cloak - a bit of controversial as well - MC can't be done while stunned.
False Oasis - Reduce scale with healing power slightly