No matter what starcraft is about acting first, and the build tree is as linear as COD's Singleplayer campaign. Resource gathering again being an age old mechanic.
I'll stick with COH where you can be on top of resources and a clever player just has to outwit you tactics wise and topple it all with just a few units.
I love both games, but to say COH is arcady compated to SC2 is a joke.
and please spare the popularity / professional league argument. That's all because in it's time it was the most balanced RTS in existence. It improved where Warcraft II literally copied the units and just re skinned them.
This has nothing to do with the differentiation between Arcady or not.