Really, image demos don't wipe anymore. Incoming 6 Grens vet 3 spam with lmg from Wehrmacht and soviet can do shit lategame...
Grens are fragile and six of them will bleed you hard. Cons could use a buff but it does not mean certain items should be kept the same. You also have Penal Battalions as AI units and rocket artillery. Demos aren't the be all end all for Soviets. Pulling its wipe capabilities won't sink the entire faction.
I mean it would be like saying Ostheer Panthers sucks so we should allow the Stuka dive-bomb to keep nuking anything within 15m of its radius.