-with the revert of id changes this has became more important than even but both classes with id and GtdC keep get the easy way merging aoe stuff with st very good stuff, these kind of build should came with great cost or not be possible. The problems of aoe copp/slayer be able to take and use aoe stuff from aoe mastery and merge it with their st stuff is due a simple too low disposition of some good tools. This change aim to separate more and so make hard or force trade-in/out , inside build picking as indirectly give some love to 2h builds.
swap both classes heal debuff with 13 pt mid mastery, this will results in a hard separation between heal debuff (st thing) and gtdc/id (aoe thing), this should enforce more the build diversity (aka mara heal debuff tactic is that high for a reason, considering choppa/slayer were later introduced post game relase is high probably the skill disposition is in fact wrong hence this proposal).
this will require to also remove/add great weapon requirement as you see fit, if i may suggest this aswell i would simply remove it from speelbreaker/no mor helpin for now and fix it later on after a periond of test.
-2h mastery would gain in deepth of spec points requirements
-st utility would be split from aoe utility and dmg
-left mastery could then be fix for his own needs with out bother too much of nerf aoe or st builds altogheter
-this wont nerf aoe builds which remain strong for rvr (and loose something they should not have for free as heal debuff), and gain something more usefull given they are the berserk classes so a bit of self heal cant do ill thing in rvr (st dmg for rvr are worst than a drop and forget heal debuff and while channeling you dant aoe --->basicaly a panic button for choppa/slaye in rvr which can be also interrupt).