I'm going to say something in the middle: if you're using grenades, you'll be doing "very good" aoe damage on par with staff elementalists, and you'd be supporting your group with vulnerability + blind + chill on the mob. If you're using flamethrower with proper build/gear, you'd do "good" aoe damage, although it's a bit awkward. I do not think however that we should say "engineer is at the top of everything" when a new perspective player is asking for suggestions, it may give off the wrong idea. The engineer has its niche, for example we can do top aoe damage + condition damage through grenades. But there are other professions who will excel over us in other situations even for damage roles alone, for example mesmers/thief/elementalist/ranger single target builds. Although we have some options (static discharge, rifle #3 + #5), we're also lacking burst damage compared to mesmer/thief/warrior (hence, why those 3 professions were at one time feared in PvP). But if it's damage you seek, you can get it from Engi. As of now though you're somewhat limited to your playstyle choices if you want maximum damage output.
Support, well, I've gotten into that argument before so I'll just say it this way: you won't notice much difference in easier contents, and by that I mean general PvE, explorable dungeons, and early fractals. All professions can be viable supports, some slightly better some slightly worse but all in all quite close. Half the professions can get perma regen/protection, the other half can get perma fury/might. Half the profession can keep perma blind/vulnerability on the mobs while the other half can keep perma weakness/cripple. Everyone can interupt/stun, some better some worse, some make it up in other ways. In higher level fractals and a few harder explorable dungeons, you start to realize why people always yell "need guardian" but not "need an engineer/elementalist/necromancer". There IS a difference, and that difference is caused by profession mechanism, so at one point we just need to suck it up and say "I realize what can I do and what can't I do, but I like playing the game this way so I'll try to maximize myself WITHIN this set up".