Ressing during a boss fight is currently a broken mechanic.
You have 5 players in a group doing DPS. 1 goes down, 1 goes to Res, 3 weakest members are doing DPS. Boss kills the Resser. 2 Down, 2 Ressing, 1 DPS/kiting (maybe). Wipe inevitable.
Res Rushing became the obvious mechanic because its faster to Res from the Waypoint than having someone Res you.
SOLUTION:
It should only take 0.2 seconds to res a ‘Downed’ ally, give them like a 1 second cripple. (no this won’t work in PVP).
Let Elixer R & Battle Rez work on players that have been killed, but not yet released.
Give downed player the ability to shield their ‘Rezzer’ from harm.