As for blade vs buffy, that... was honestly a snooze fest. Analysis from what I can tell was alright at least, with a few neat gags, but right from the jump of the fight, I was thinking 'did this really need to be a Death Battle?'. Not in MU potential or dynamics per se (I know nothing of either character's greater history), but in direction (it felt like it wanted to be, for lack of a better term, it's own thing, when the great thing about current DBa's is that they actually get vaguely straight to the point). I find myself reminded of an Overly Sarcastic Productions video on idiot plots where 'some conflicts could be resolved with 10s of punch-free communication', and that's another one of my bigger problems with the setup, not helped later in where Blade is halfway through explaining why he shot that wanton sacrifice, only to stop randomly then get headbutted/thrown off by Buffy. It was also out of line for Buffy to wise crack about Blade's lost head, when the entire reason she wanted to pursue a fight was because of one girl lost to the vague cult shit.
As a corollary to the above - Compare in KratosAsura when Asura first throws a punch, to when the actual 'Blade vs Buffy' part of the fight actually begins. Keep in mind how KratosAsura is also dunked on for being slow and clunky. I think you know what I'm implying.
I've also heard it critiqued that Nightwing vs Daredevil felt too much like 'two actors trying desperately not to hurt each other', and that goes doubly here. The FX are quite evidently phoned in, and they look tacked on as a result. See again the above KratosAsura comparison, and how few attacks are thrown there, it feels similar in BuffyBlade IMO.
3 or 4 / 10 IMO. That race for the bottom is going to be close.