Honestly, some of the largest changes for GT22 is all the extra Actions required, and more use of the angled/quarter deployments. Also lots more objectives to fight over, altering how much players can lean on Stranglehold and Banners.
From a DE perspective, not much has changed. Raiders now give up 2VP for Bring It Down, which sucks. If you have units to score you RND, they will likely be units of 6 (mandrakes/scourge).
Dark Eldar still dont have a standard third secondary to pick. With the VPs increased on 10W vehicles for Bring It Down, and the increased VPs for No Prisoners, the third pick is actually getting easier.
Having a character or durable unit to sit back on objectives and do Actions isnt a bad idea. Haemonculi are decent for this role, since they basically cant die.
Thats my $0.02 anyway