It seems absolutley bonkers to me, but I actually kind of like it. I wouldn't want to play 6 games in a row against it at a tournament with Fateweaver and Magnus flying around making my life miserable, but in a pick up game every once and while I think it'd be awesome.
Its totally over the top, probably be super frustrating to play against but I love Chaos having either that raw intimidation factor like Emperor's Children, World Eaters, Death Guard and Iron Warriors will certainly have now... or the weird factor like Thousand Sons will be bringing to the game where you drastically have to shift your approach to the game... sort of like playing against a mixed Eldar factions Leadership Shenangigans with spearheaded by Harlies, DE Pain Engines etc. where whatever unit falls under their eye finds it nigh impossible to make leadership saves and just runs off the board due to psychic horror.
I've listened to the break down on a number of podcasts, mainly Signals from the Frontline and it is bananas. But it so easily matches the fluff, and it seems intentional from a rules perspective... especially considering how ridiculously expensive each of the Thousand Sons rubric units are. You can actually invest in those units and have ungodly hordes of Horrors running around. I'll be interested to see how actually plays out on the battlefield... that'll be the ultimate barometer for me.