I personally think this is more powerful than dimensional shield as it is. Yes, you can list more "counters," but these counters require a player to use them in a way that's not usual, which makes them significantly less viable. Just think about SoSa. People list sundial (to stop your own creatures from attacking), antimatter, liquid shadow opponent's creatures, etc. as "counters," but I don't see anyone successfully using them that way.
Another point that I don't like (and part of the reason why this is better than dimensional shield) is momentum being blocked. Momentum in this game is defined as "ignore shield effects." This is a shield. I saw your justification as to why momentum is blocked, but I don't like it.