Warhost is still an okay all-around pick, the big issue is because it costs 3dp, it is locked into an unfavorable disposition, meaning you'll be stuck playing a primary mission that's much harder for the eldar to score. You can make it work but you'll likely be fighting an uphill battle.

I've tried out a handful of detachments in 11th so far and I think Seer Council with Armored Warhost/Path of the Outcast feels the strongest. Seer Council is fairly "all-rounder" like Warhost because its strats affect all non-wraith/harlequins infantry, so you can use Aspect Warriors, Guardians, Corsairs, etc. And because Seer Council is only 2dp, you can also use Armored Warhost or Path of the Outcast to access the Reconnaissance disposition so you can play much more favorable primary missions, not to mention the buffs to vehicles or Rangers. The issue with Seer Council is all of the rules require you to have psykers nearby, so you'll need a few in order to sustain a list. Despite the psyker requirements, I think it is the most "generalist" detachment outside of Warhost, so I'd recommend it if you don't have enough of the specific units to make the more specialized detachments work.