Yeah, I'd wait till the new air book comes out just to see if it's any huge shift in the meta.
Other than that, definitely get a farseer or 2, at least 2 units of bikes(scatter optional), some swooping hawks, and vaul's wrath batteries.
All of those work well supplementing DE. If all of DE are a hammer, then vaul's wrath batteries are their anvil. T7 vs shooting with 48" guns at 30 points per gun + crew is a really good price.
If you consider that a normal guardian is 9 points, and you get 2 of them with each artillery gun, then you're only paying 12 points for a T7 gun with 2 wounds and a 3+ armour save that also makes your guardians T7 vs shooting. I tend to use them in units of 3 vibro cannons, purchased in multiples of 2 with 1 attached farseer for each 2 units of 3 vibro cannons. Then I take the guide and prescience primaris powers, and twin link both units all game, which basically makes them put out 3 S9 AP2 pinning hits per turn, per unit. I generally place them so that both units are scoring the same objective in my deployment zone, and overwatching as much of the table as possible.
If you give them a good cover save, killing 1 unit of them via shooting becomes similar to trying to kill a wraithknight. They don't have FnP, but they have twice as many wounds.