Cons, being generally close range units, wouldn't profit much from the DP MG. PPSH is not really that bad, even at 2CP. In teamgames, unless it's a map like Ettelbruck, you won't really go for it.
One thing I've seen done successfully though, in 3v3 was this:
Double mortar + PPSH cons. Mortar smokes for cons to close in. Rinse and repeat the whole game (also advanced WF commander) until T3485s.
I am going to hard disagree with this. DP upgrade would be even better than the SVT upgrade for cons. At VET0 cons would do about 11.6 DPS at max range with over 50% of the DPS concentrated in one model and a 4/5 model buffer before needing to retreat. They also get the efficiency buff of LMG focus fire that could cause RNG to swing their way on approaching units. They would be even better than Grens as cons would be able to pick any spot on the map and make green cover. As an OST you would never take that battle unless you have your own green cover in the area/OKW would be fucked the moment DPs come on line.
Now comparing them to Penals max range- At Vet0 cons would do 11.6 DPS while Penals would do 10.8 DPS. As cons can tech AT nade they don't have the LV weakness along with sprint to relocate and sandbags to preserve MP. I would assume Cons would vet faster due to AT nade/flame nade boosting exp generation a bit.
Now at VET2 cons would do about 17.7 DPS where it would take until VET3 Penals to outclass them and it wouldn't be by much. Serelia has Penals doing about 20.6 which is using the old 30% acc at Vet3. I know its rough but subtracting 10% would drop it to 18.5. Aside from early bullying, there would be no point to Penals.
I used Serelia Guards Infantry numbers for DP DPS, for some reason Airborne Guards have a different starting acc compared to Guards so one is a mistake not sure which. Technically the Cons number is a little low as the get 40% acc not 30 with VEt
EDIT: Just realized that the DP is an upgrade for cons at all ranges not just long range LOL. Man their base gun is shitty.