I've played mostly RD and COH, but not as much MOW, here's my $0.20 on what you can expect different from those:
- Gigantic maps, even the "1v1" and "2v2" maps in RD are bigger than the largest 4v4 in COH
- No base building
- Deck building, which you have a limited number of points and you choose your combination of units. It's got mechanics that are not in COH and MOW like unit starting experience
- Limited units, you only have so many of a unit, you get them all killed and they're gone forever
- Logistics, you can only place supply dumps before the game starts and call in supply trucks after, if you run out of supply then you won't be resupplying and repairing anything for the rest of the game
- Controllable air units, you buy them for points and they will be in an off map airport forever, without having to pay "ammunitions" every time you call them in (Might change though given how some people don't like free air power in RD)
- Cover is area based, so you've got forests like areas or hedges that give cover as long as you're in it, no need to micro stuff into them
- No unit abilities, you will spend your time macroing multiple 10-men units instead of telling 1 guy to throw a grenade or something
- Recon is more important than ever, your normal units are pretty bad at spotting stuff, you need dedicated units at vantage points
- Behind the line actions, given how the maps are you'd need to actually protect your flanks from infiltrating units. Its totally possible for a single infantry squad to sneak past your lines and destroy all your artillery if you're not careful
The most important aspect of SD44 based on WRD imo would probably be scarcity. You can specialize and be really good at 1 thing e.g anti-armour, anti-inf, and be completely useless at other situations, or generalize and lose out to specialized decks, you have to pick and choose what you want. Also you only have a limited amount of everything and you have to keep that in mind the whole game, if you lose/use something its gone for good; sometimes its a good idea to send all the infantry you have left to take a town, sometimes its not. You can fire off artillery after artillery in the beginning but once you run out of supply you're literally screwed.