Hello mate, I've been using the ppsh a lot in this game and I have to say I kind of disagree with you, just played couple of games on apartments and barracks, I scored 42 and 31 kills with the ppsh41 standard mag. I have to say it handles differently than in ROOST, but it's not only the gun itself it's the whole mechanic of the game, I'll explain better:
In ROOST the whole game was a lot slower, running was slower, aiming actually wasn't instant as it is in ro2, firing while walking was very hard (IS mode), all the weapons handled differently, you actually had to click mouse button 2 wait 1-2 seconds and then you were able to shoot, also the no zoom thingy made it harder in ROOST, also keep in mind that there were far less smgs available in a team. So basically the whole movement and firing mechanics were different, and in that enviroment the 71 rounds ppsh really was the weapon of choice in very close range combat, you could unload it on hordes of enemies without them even returning a bullet back, it was perfect for cleaning rooms and trenches.
In RO:HOS it's a completly different weapon because the mechanics of the game have simply changed, now you don't have that delay after you click the IS mouse button, you can instantly aim&shoot, and this applies to all weapons, thus making them more effective in CQB (all of them), here you can walk&fire with no penalty at all, the little sway is compensated by mouse movement, and you can easily sprint away from a bad CQB situation, also the game pace is faster, less tactical and more spray&pray in CQB, in this kind of enviroment the ppsh41 shines a bit less, but it hasn't lost it's effectiveness in CQB if you use it correctly, in ro2 you have be as fast as possible with the ppsh and aim very well at your targets, 1-2 bursts each enemy only, no longer whole 71 mag unloaded into a room, the best way to use the new ppsh is basically that, using the easy aiming system of ro2 to quickly kill the enemies and then sprinting into the next room, and repeat, with the possibility of mid range fighiting which wasn't possible in ROOST giving the inaccuracy of the ppsh.
Do this and you'll get as many kills as I usually do and have a lot of fun! It may seem a bit CoDish but it's the way the gun works in ro2.
Ps: you no longer need hipshooting because aiming is instantly possible