So apparently it's not their flamethrower that bothers players, it's the CQB as i expected. I haven't seen anyone saying "Stumpioneers are very strong, they need to be changed". Since i started this game it blows my mind that Engineers are able to beat well trained soldiers. Again, my suggestion is this : Change AE's default loadout. Change one of their Grease guns.
You imply combat engineers were not/should not be combat effective units.
Combat engineers were elite troops for all factions.
Combat engineers were/are often expected to lead the assault before the infantry in combat situations.