About the blood, they already covered possible blood consumption in All Might's post Stain debriefing where he assured Midoria he wouldn't lose his powers unless he specifically willed it, meaning this should be covered as well.

Tolerance of Shounen tropes is what it comes down do, and Nighteye stretches that a bit farther than the rest of the fights so far. I also didn't care for his heavy weight stamps, but the author must have thought it would make a cool looking weapon, so here we are...

Just a thought, but one thing that sticks out to me as a bit subversive to shounen about MhA is that the author does very little to quantify how dangerous the characters are aside from their quirks' properties. On the one hand, this makes sense as the fights are predicated on the application of powers and their match-ups/strategies, but can work better (in my opinion) with some more baseline power rankings like Nen and Haki from HxH and OP specifically. By having baseline (relative) power-levels defined for the audience somehow (perhaps just visually), match-ups can serve as the base for the actual tactics, as in a disagvantaged fighter will fight conservatively and so on... As this is, MhA fights can feel somewhat random, or forgone, as the audience has less to speculate. The extreme example of this that I'll always loathe is Fairy Tale, who's cast could have never changed and I'd not know any better, but that's another rant.