Yeah the current Necrons are terrible, both lore and design wise. The models/art is too over-detailed and appear to be made for 10 year olds literally, with cliche scythes for " undead robots " to largely the same skeleton heads on each unit, save for deathmarks. I doubt they'll drop the whole egyptian theme, but at least hope the units get a remodelling in next codex, cause they'll simply terrible. At least remodel the heads to be somewhat unique and screw those ugly crowns.
As for lore wise, I expect them to do something actually important, like smite the nids and establish themselves as number one enemy to Imperium.
As for Necrons getting flesh bodies again, I doubt it will happen. Lore wise it would make sense and they're actually trying to pull that off but tabletop wise I doubt they'll change the whole gimmick. People came to love the soulless undead machines, not some " we don't even know how they looked as necrontyr " fleshling race.
The trouble we have with the necrons is trying to find a balance between "oldest and most advanced race still around" and "doesn't have the ability to wipe us out." The older iteration of necrons were basically extensions of the wills of four vastly powerful gods with little or no will of their own. They were cold, unfeeling and existed only to slaughter the living and feed their deities. Their knowledge and abilities gave them reality bending powers and made them basically immune to the permanence of death.
The new necrons are self centered egotistical space politicians/conquerors with massive superiority complexes stemmed from the fact that they defeated their own fucking gods. They have limits however, relying on an old failing technology in order to maintain a crumbling galactic empire of sorts as they try to reclaim what they lost eons ago.
See the issue here? You're torn between Chaos 2.0 or Eldar 2.5, there's really no other trope that hasn't already been covered by some other race. Worth pointing out however is that the current lore at least allows for glitches in tombworld technology that destroys sleeping necrons' identities. So you can keep the silent soulless oldcron theme and motif if you wish. Both are just as valid.
If I was to remove a race, it would be Tau only because they are the least influential in the overall of 40k. To bump one up? I don't know, everyone else seems to be sitting exactly where they should be.