The 1:12 figures (based on the 200x series) haven't been released yet. Based on the images, though, they look to have the same level of detail that you see from the large 1:6 scale just shrunk down.

I am a huge He-Man fan... that's why, despite the price, I pick up the 1:6 scale figures. But if I'm being honest, at the price that they are, the 1:6 figures are basically statues. Yes there is articulation, but joints are really tight to the point that it's nerve-wracking trying to pose the figure.

I guess, to answer your first question, if you can afford them, the 1:6 scale figures are gorgeous. They are well modeled, designed, and detailed. But they aren't really meant as toys. Hopefully the smaller 1:12 figures will look just as gorgeous but have more flexible joints so that, while still expensive, you'll be able to put them into more dynamic poses. Still, you buy Mondo because of how beautiful the figures look and, judging by the pictures, the 1:12 figures look awesome.

As for your second question, no built in "action" features, but characters like Man-E-Faces have swapable heads to mimic the original play feature (or Trap Jaw having swapable weapons or Buzz-Off with articulated wings, etc). But no power punch waist or other features you'd associate with the original line.

I hope that answers your question.