You don't actually need many hearts, Mehrunes quest has four which will get you the complete worn armor set. I reckon you could easily find a couple more just while adventuring for those final few pieces if you were patient, I'm not so I just shopped alchemists and stole one from the companions in Whiterun (just lift the heart up and run off down the corridor with it ).

It's certainly pretty wierd and inconsistant to the lore...

Still, at least when you use the Atronach Forge you feel like you're using something special.

Better than in Oblivion when every man and his dog seemed to have their own personal connection to Oblivion! It was pretty RP crushing to walk into a cave and find all the enemies decked out in "uber rare" daedric armor.

Maybe the Hero of Kvatch started a black market running daedra hearts out of Cyrodiil...

Not sure, I've never called a dremora at the forge before...

I seem to remember that a Black Soul Gem + Human Heart will create a Daedra Heart. There's a couple of cool recipes you can do...

Quick Shot + Bound Bow is a waste, barely any improvement...

Block tree would also have been a complete waste. That daedric shield stops anything like I mentioned in the build, bound bow keeps enemies off you, conjuration keeps enemies off you, sneak keeps enemies off you...

...sneak got so good that once a dragon landed (dragons seem to lose a ton of their detection ability when they aren't in the air) they were done for. I was standing in front of one landing stealth bow shots at one point.