Well, it is setting him apart. The Assault's theme of DPS is crits. Many, many crits. Rifleman has jack of all trades DPS, and Opsmando has burst damage. There are other DPS classes, yes, but they branch out into different things (SubMM being burst/movement, CEngi being sustained/minion, so on and so forth). The merits of Overwatch over Total Annihilation are that Overwatch has the Assault continue doing what he's been doing for the entire tree: More dakka, better dakka. Total Annihilation was cool, but he was essentially pulling a Missile Pod out of nowhere and blowing things up. Also, even now, the Combat Engineer doesn't outdamage the Arms Assault unless Overdrive is active, and I'd daresay that it's fair to leave T3s out of the comparison at this time because the Assault's is so non-conducive to increasing his DPS. Once this goes through, the Arms Assault Assault will be capable of outdamaging the Combat Engineer with ease, which I'm perfectly fine with (considering that the Combat Engineer has way more mobility than the Arms Assault does).