Personally, I think a mix of features from both series would make a better game.
I liked the frontline of SD44 much more than the WG modes, feels like its prevents stagnation.
The logistics in wargame was much better and I'd prefer if they returned to that.
The division/Battlegroup templete is a mixed bag for me. I agree that you can kinda expect what is coming from certain divisions and certain divisions are much better than others but in the WG battlegroup certain units almost never got used because there were better options. Like you would almost never go the captured french tanks in a panzer battlegroup if you could just get panzer 3+4s, Tigers and Panthers.
The surrender mechanic and vet mechanic are both interesting and debatable. The surrender mechanic made it very punishing for over extending without support and both the vet and surrender mechanic made command squads/vehicles very important to succeed in the game. Maybe if suppression was lower or it wasnt so easy to suppress surrender squads or vehicles than it would feel less gamey.
SD44 also felt slightly smaller scale and much slower. I also found it more difficult than WG in my opinion.