Rather than immediately latch onto the negatives of the fluff, why don't you at least try to interpret it in a way that is satisfactory to you?
That would be the equivalent to someone telling me "Instead of not liking Joel Schumacher's Batman and Robin, why don't you just look for the positives to this interpretation of Batman." I could use Episodes 1-3 of Star Wars or the last Indiana Jones movie with the alien skulls for examples as well. Sometimes shit is just shit and you can't sift through it without getting sick.
I know a lot of people preferred the necrons as soulless killing automatons, but the fluff provided still allows for a necron force to be exactly that. Tomb worlds can malfunction, necron memory banks have been erased rendering entire necron dynasties as little more than vessels for a single all controlling AI. The old necrons you supposedly preferred are still there, only now there are other necrons with more variety for those who prefer that instead.
Where the creatures of the Warp thrived on manipulation and dominance, the C'tan and Necrons offered oblivion and destruction. They served entities that fed on the souls of living creatures. The fluff for the Outsider, Void Dragon, Deciever, and the Nightbringer was badass. The original fluff made these things the antithesis to the Chaos Gods in the material universe. The option existed that, like the Chaos Gods, you could have different Necron factions dedicated to each of these gods and develop them like you have the Chaos Daemons. Instead, the Necrons are now working with Astartes and the C'tan are controlled and contained largely. What's the point of them now?
Dit to the c'tan, sure a lot of them are under necron control now, but the fluff also still allows for rogue star god shards to wreak havoc across the setting, and it is also made quite apparent that they are no less destructive for their supposed defeat. So what if the Emperor only beat a mere shard of the Dragon? Even a shard of a c'tan holds world ending power, so that deed is not diminished in the slightest. Same can be said for Uriel's battle with the Nightbringer, now assumed to be a shard, it still escaped and is now free to cause who knows what kind of harm elsewhere.
The Emperor defeating a star god who was barely at full power and the emperor defeating a fraction of a star god who was barely at full power means a lot. Same thing for Uriel. Imagine if instead of the Emperor defeating Horus, he defeated a shard of Horus and still got messed up as bad as he did. You'd start doubting his true power. Having to retcon the original fluff takes something away from where many readers imagination went. From the fluff with the Old Ones and the original War in Heaven to present, the Necrons now are like a more conservative version of the Tau.
Don't like the Blood Angels and necrons team up? The short story Word of the Silent King fixes that anyway, by making it apparent that there was never more than an uneasy truce at best, and both sides fully intended to screw the other over at the earliest convenience.
The Necrons like the Tyranids and Chaos originally were a force that wouldn't need to "team up" with anyone to achieve victory. Why would primordial killing machines fear Tyranids? They don't even have any biomass to consume!!!! Now that they are pretty much machines with feelings, they feared defeat and destruction and went into an alliance. You think warriors of Khorne would have allied themselves with the Blood Angels? I don't even think the Orks would have. Basically the Necrons now rate a level above the Eldar who also would have found a way to screw humanity to their benefit.
Don't like Draigo? Well I can't help you here. I think Draigo's fluff is fine. In fact of all the denizens of the Imperium of Man, I find his story to be the most hilariously tragic. Possibly the greatest hero mankind has to offer reduced to a mere plaything of the warp gods, doomed to show pointless defiance to his captors until he finally breaks and gives up.
While I agree that his warp triumphs are completely pointless I don't think that's what pisses most people off. We read in the Emperor's Gift the sacrifice and struggle for multiple Grey Knights to just banish a daemon primarch. Now you're telling me this guy defeats him one on one, maims and humiliates him? I'm a GK fan as much as anyone but that's bullshit. Tales of Primarchs wading through the way more powerful original Astartes are well known and now this random GK man handles a primarch? C'mon.
It's not that hard to see the bright side to any of these, or the dark side if you prefer to think of it that way.