No Mercy is flexible enough to fit everything with 2 extra seconds, if you can't because of some reason that's okay fitting 7 GCDs.
You can also fix the "ping" issue by making No Mercy 30s but expire after 8 GCDs, similar to Delirium or Hypercharge.
The "DPS stress" works fine in GNB, it's the same as positional except it's exclusive to GNB. That's a job meant to catter to DPS who wants to play a tank.
Those are the concerns I have with GNB:
-Forced downtime reduces cartridges generation.
-Bow Shock/Blasting Zone are still the biggest victims or drifting
-Damage variance during burst
-Bloodfest remains inflexible if you want to use it earlier you have to use it earlier in your complete rotation.
Except damage variance, the rest is pretty much between our hands so these are just that, concern.
