yes, healers are only used in raid or sometimes in domi
for heroics thers no need as engineer healing inaf
having +1dps insted of healer making that mobs die before healing is needed, thats why enginner % heal from pover barier, sometimes from medical emergency, and in panic button, Sanctuary( Portable cannon) is good inaf to burst mobs/boss inaf fast to avoid potential errors making team to die, when with healer fight is 1/2 longer
- is tho enginner is more rensponsable for team, if he die, team lose all sorce of dmg/bloodlost and survability, also supports like engi/bard have 3-4 stuns, witchout that your team is in big lose, if you not ress engi inaf fast
so if you have unexperienced engi it's better to take healer, but it will make fight longer = more harder
to make engi not wipe eazy, demonologist can use -40% dmg for 10-12s, or paladin use team heal/absorb when you see enginner having problems, as cuz on sup he do less dmg = his more squshy as he building less concentration from dmg
druid or summy heal skill are saved for tank, if his health drop too much, as thay have acces to that skill even when thay are od dps, and it's good to have druid+summy in team, as it's +2puri, so engi medical emergency can ba saved for situations when instadeath debuff is on more than 3-4ppl
both summy and druid have huge pet burst ultimate skill as well what is healpfull to kill boss fast
last slot is rezerved for bard as it's sup class oriented, so even in dps he got 3-4 stuns to help engi when other dps class have only 1, max 2
if thers no bard in team, you need use aodis fire insted as whole team
at last it's my experience as person who finished lv 25 heroic