Sorry, about a week behind in reading, had a friend and family from Spain over here last week.
All good man!
If BW suggests that rolling into a wall and having all of the bombs land in one place is "working as intended" then that's something else.
I'd personally won't think that that was their FIRST intention, but more of a clever use of game mechanics
We will never know until the devs tell us directly what their intention was for all 3 specs (NOTE this can be a good question and we can ask it if more people vote for it), but this is what i think:
Lethality = DoT spec. Long ramp-up. Can spec for spammable AoE slow via CG DoT.
Engineering = AoE- area denial spec.
MM = turret down spec, cover immune to Charge, entrench immune to CC.
Lethaliy's roll = Corrosive Mines, has a little AoE damage but more importantly used to kite and slow enemies. Can be used to give you time to apply your DoTs while the person is trying to get out of your Corrosive Mine AoE slwo.
Engineering's roll = AoE dps and leaves 5 bombs throughout your 18m covered escape.
MM's roll = gives you X seconds of entrench for immunity CC to let you turret undisturbed. Movement speed buff after leaving cover to help you reposition.
@islander - no vote yet? :P