Malfunctioning Tomb worlds has little resemblance to the old lore. The story used to be about a terrible dark and powerful entity leading the remnants of a powerful race. The story had a mysterious plan of a the C'tan, hinted at in the Codex that could be gleaned by Necrons fans but was often missed by players who never collected them. The story also had battles and events with unknown agenda and confusing purpose.
The plot progression was set up magnificently. Remember the bit with the Farseer who had a ship in Orbit of the orphan planet the Imperium used to train Culexus Assassins? He had a flash from the future showing Eldar suffering and wiped out by a mysterious foe if they proceeded with their plan, so the Eldar aborted the plan.
Lots of plot and little text. Clever writing from a brilliant design studio.
All of this was gold and a set up for future releases or a campaign.
But no, we don't get that any more.
I appreciate your thoughts, but there’s no reason why any of what you just wrote has to be invalidated by the newer fluff progression. The Necrons had to adapt and evolve. The mystery to the race is still there, and we now have an infinite amount of possibilities going forward with the presence of thinking phaerons and Triarch candidates. And again, absolutely nothing stops Tomb Wprlds from being any more mysterious and self serving than they were in the past; they’re just not all pigeon holed into being “mindless automatons, because creepy.”
For me, I’m curious to see if anything is done with the Void Dragon on Mars, the Dyson Sphere the Tyranids avoided, and where the Silent King went and what he was doing.