Re: What blocks senses and powers?
I'll do my best to answer just the questions. I'll put my opinions at the end.
1. The enhanced sense you've discribed is bought with the range advantage, but sight by it's nature is a ranged sense, but it gets stopped by trees, people, rain, fog, hazy air and plain old walls. IMO, this power should have some limiting factors to it. Sensing water through dirt is one thing, sensing it through layers of rock may be a complete other. (I can also see Air Conditioning being a huge PITA for this sense)
2. The microwave EBeam is a fun little toy. But like all toys it needs to be paid for fairly. Invisible to sight, is a must; AVLD or NND, player or GM's choice; and if you want it to effect anything beyond a wall, Indirect. The heating metal and water are just a "color effect" of the description of the power.
I think the "sense water" power is kinda nice, it fits a character and I'd allow it, but if a player of mine used it in the ways described I'd have to take them out behind the woodshed for a little talk.