I’ll keep this brief. I like consistency, and yet why are there only three professions that have party-wide stat sharing? The ranger gets Spotter (precision), warrior gets Empower Allies (power) and guardian gets Strength in Numbers (toughness). Hell, guardians get virtues and the Battle Presence trait too (shared virtue of resolve passive) so they get superior party support to all. Elementalists get Soothing Mist, which is good stackable regen to keep you topped up against splash damage.
This leaves several stats which haven’t been shared out yet in a trait on any profession. I believe above all else, thief is lacking in party support in terms of DPS aid to party members. Mesmers also have Time Warp, forgot to mention. The only thief party aid is stealth, which is the opposite of DPS aid.
So, to combat the inconsistency, I would recommend that thieves get a party-wide ferocity buff to a party of 5. 150 to keep it consistent with Empower Allies perhaps. This would make sense considering the crit damage nerf to stats; a supplement choice would be great and make thieves more desirable. In PvE, they’re not really a favoured profession due to their squishiness and lack of party support. Backstabs do great DPS, but more often than not in PvE you fight mobs where backstabbing is wholly ineffective compared to an ele, guardian or warrior.
Of course, the next obvious suggestion is a shared condition damage for necromancers, but I doubt that will have much affect on the profession. They need far more help than a trait change. Elementalists could have Healing Power sharing in water, too.