So popular it got canned due to not bringing in any money from the users, even with nearly zero development costs (a couple new menu screens, some new server code, and rearranged command trees). A high standard to try to achieve
Allies would never win a game again if lone machineguns could stop 5 infantry units charging them.
Playing against mine spam is already boring for all parties involved, slowing down sweeping would make it twice as bad.
It got canned 1 or 2 months after having implemented the micro transaction system with really few option in it. And honestly looking at how Relic implement stuff and how they support it. The failure wasn't coming from a lack of player enthusiasm to spend their money...
The game was doomed before they implemented money transaction, and the worst it that they knew it and still implemented it to suck as much money as they could from their playerbase. Erk, You make me remember that just know, it is not going to improve my vision of Relic. Disgusting company...
Now about Gren/MG42 synergy. It all comes from they stupid early design.
Sov = assault infantry that need to close the range to deal damage
Ostheer = LMG faction that need to keep the range to deal damage
USF comes with WFA = mid range faction murdering grenadiers early game