Obviously blood tokens are good as this sort of smoothening mechanic that stuff like clue tokens, scrying, and cycling are. That does nothing to address the fact that they are a huge swing and miss as far as flavor goes. Something that should be so flavorfully intrinsic as "blood tokens" are now forever relegated to have this obscure connection of flavor and mechanics that just don't connect.
Going to that linked article about blood... How could they possible start with blood tokens with the implicit reason to go for them that they are so deeply tied to the flavor of vampires and represent them flavorfully, only then to conclude that actually the flavor isn't that important after all. Like why the f would make a mechanic that is entirely top-down inspired and not make it resonate properly? The whole concept spawn from blood being so resonant and then you essentially ruin it by attaching functionality onto it that doesn't represent it. It's like, idk, taking the name of some franchise and slapping it onto your movie when it doesn't really have anything to do with, just because that name itself is flavorful but you don't see it being important to fully represent the name. This is absurd.
If you fail to do the flavor of your entirely flavor inspired theme justice, then it's better to drop it altogether and leave it for another time when you can actually come up with something proper - not to use it despite having anything excellent for it and now desecrating it for all time. This is now what blood is - and it's wasted. And it's not only wasted on the blood side, but even on the rummaging side since that's a good general mechanical concept that would be well utilized for something very general that can be reused in different contexts - blood is very much not that. Like a
really bad combination here of taking a very general use mechanic and tying it artificially into a very specific sort of flavor connotations to which the functionality doesn't reflect at all.
Oh yeah I think the last truly great set was the original Innistrad so eh. It's not the like the ideas aren't great, these are something which I and many other custom designers have tinkered with previously - an egyptian set, a norse mythology set, a dark fairy tale world, "planeswalker set", etc - the execution just quite isn't there and there are several reasons for it - both in design and in development from what I can see. Like, oh man, this new Kamigawa 2 has me bumfuzzled completely but those rants are for another thread I suppose.