.....I think I disagree but I want clarification first. Where do you see the needless complexity coming from? I would contend the problem isn't complexity (I actually rather like that) but the ongoing imbalances and the fragmentation of the special rules through formations.
At the end of 6th I thought we were getting back more to a better place. But 40k in my opinion had been seriously watered down when they switched to 3rd Ed. I despise the AP system. Save modifiers are far superior. Every edition since 3rd has slowly gotten closer and closer to 2nd ed.
To me needless complexity is a number of issues,
1. Random table rolling where points could be spent for abilities. It doesn't add "flavour", its just annoying.
2. Assault and challenges, as an ork player this has become just so laborious and off putting as to not want to bother.
3. The complete overhaul of the flyers in the game. TBH, I didn't actually bother to play this part, so it maybe more streamlined for all I know, but it seemed to me that adding another phase is not exactly going to help matters, even if its voluntary or not.
4. The Rulebook. It's just horrible to use. You can end up jumping back and forth through it for clarifications, and it just slows the whole process down. The layout is also not to my taste.
5. Multiple Codex's and supplements. Again, as an Ork player I have a number of books to use, plus FW's IA8. It's a huge pain. Lots of lovely detail and fluff, sometimes, but really just crap to use. Plus an opponent may have just as many, We shouldn't need to have to have 3-6 complete books just to play a game. This is where AoS wins out for me, Dataslates with everything you need in front of you. I also play a lot of X-Wing, and I appreciate having everything I need right in front of me and a simple game mechanic.
That's just a few that I can think of off the top of my head, I just hate rolling dice for no real benefit. Roll to hit, roll to wound, roll to save, roll for FnP, roll for Ld etc etc what a pain in the arse. That's upto 5 rolls to attempt to kill something.
X-Wing proves that a game can have complexity and strategic depth but have a simple mechanic. You roll to attack, and to defend. That's it.
I wish 40k had something similar, I'd probably come back to playing it if they do sort it out, but at the moment I cannot invest 4+ hours to play a game. Christ the last game I played at 2000 points it took over 6 hours, and we only just got to turn 5! My back was killing me towards the end.