Starcraft 2 just isn't a very flashy game, and I think screens of the gameplay really undersell it as a game. They should really rely more on trailers and concept art to sell the title, where everything looks way more appealing. That being said it is still, from what we know, an extremely conservative design from Blizzard. We'll see how things play out at release, I imagine that the fact that there's not much "new" going on will be trumped by the mission design in the campaign and the multiplayer, where pretty much any competent RTS is awesome becuase multiplayer RTS games are just that awesome.
The x-factor for the game right now is sort of what they are going to do with bnet in terms of features and improvements.
Regarding Red Alert 3-the color palette being used is very vivid and the blue oceans and green grass are a very welcome contrast to burnt-out yellow and red zones from C&C3. I think that's one reason why the game looks so good, along with the great unit design and aesthetic.
There's some deeper stuff going on in RA3 though than just the visuals. The economic model has been overhauled for the first time in the series-it's now node, not field, based, and each node works on a 'one harvester, one node' basis. So there will actually be some rhyme and reason to the economy instead of the previous games' tendency to harvestor spam for a megaboom (and then bust when the ore runs out). There's actually a chance that we'll see a smooth transition from tech levels and such.
I've got my beta code registered from my copy of Kane's Wrath and I'll make some commentary when that goes live (which should be pretty soon).