Well, that depends on what you want the Swampert make.A Swampert support of stealth rock is good, but if you already have a pokemon that puts stealth rock field you can use it in other ways, and this was one of I found, though it is very unusual, but in general I use it as well and it works great until, despite the stelath rock Swampert be better. And you're right about not having to recover, leftovers in Swampert is very good
I my opinion, AV Swampert isn't good in the actual metagame because :
Like you said, it hasn't recovery, so its bulk will be lower than the Leftovers set, and it doesn't hig very hard like AV Azu, it will not be a good offensive pivot like Tornadus-T because of his lack of recovery...
This AV set doesn't touch many things in the metagame, so, maybe it will tank some thing, but it will not hit hardly in return...
252 SpA Life Orb Latios Draco Meteor vs. 252 HP / 0 SpD Assault Vest Swampert: 200-238 (49.5 - 58.9%) -- 98.8% chance to 2HKO
(Unfortunately, Latios deads on the recoil because of Ice Punch)
252+ Atk Swampert Earthquake vs. 0 HP / 0 Def Keldeo: 175-207 (54.1 - 64%) -- guaranteed 2HKO
(Only 55% ? :-/ )
252 SpA Choice Specs Keldeo Hydro Pump vs. 252 HP / 0 SpD Assault Vest Swampert: 195-231 (48.2 - 57.1%) -- 91.8% chance to 2HKO
It doesn't like that (and fears the burn of Scald)
252+ Atk Swampert Ice Punch vs. 4 HP / 0 Def Mega Altaria: 148-176 (50.6 - 60.2%) -- guaranteed 2HKO
In fact, it's a basic Swampert, without Stealth Rock, and Leftovers, the only qualities making it "good". The AV take just easier few hits.
But, you know, it's my opinion ^^
(Excuse my bad english, i'm french...)