Okay, so I've played enough 9th Edition games to have come to the conclusion that, in my opinion, this edition is fairly badly broken. Now, we all know a new edition is coming in the next few years, so let's talk about what, if anything, you would fix or change about this edition to make it better.
1) Streamline Pre-game Process
I think the whole thing of setting up the terrain (after mission), the weird measurements of all the objectives (9" this way then 6" that way, etc.) and the selection of secondary objectives takes way too long. I also don't like the alternating deployment stuff, which I think takes way too long.
I propose having secondary objectives FIXED (as part of your army list, not chosen at the time; I'm aware this would require a different set of secondary objectives in many cases) and go back to the old 5th edition roll-off--you either deploy everything first and go first OR you deploy everything second and go second. I think this makes things go faster and is more interesting. Bring back Seize the Initiative, if you like, but I preferred that system by a LOT.
2) Change to Armor Penetration
If there's one thing that Armour of Contempt has proven to me, it's that the current rules for AP are straight-up broken. There's too much of it, it's too easy to get, and its too powerful most of the time.
I'd like to see either a RETURN to the old tiered AP system (which, honestly, there was nothing wrong with) OR a severe reduction in AP on most weapons. Just, like, remove it from most stuff. Let people take their armor saves.
3) Shooting is too powerful/Cover is too weak
I've heard it said from numerous people that an "appropriate" amount of terrain in 9th is enough LOS-blocking for you to hide most if not all of your army on turn 1. I'm sorry, but that's ABSURD and speaks to a severe problem with the game. Not only does this limit the kinds of battlefields you can play on (which is boring), but it also indicates the shooting phase is entirely too powerful and cover just doesn't do anything.
My recommendation? Bring back cover saves! Cover saves were great! They were simple! They kept things alive long enough for you to maybe see Turn 4! All this +1 Armor save/-1 to hit nonsense is just silly, since it almost never actually matters that much, especially given how prevalent AP is.
4) Faction Rules/Scoring Need Streamlining!
The rules bloat in 40K has quite literally never been so intense as now. Balancing and keeping track of all this garbage, even in a single army has become untenable, especially for a new player. I can't even imagine being somebody trying to get into the hobby these days. And then the scoring? The last time I needed to do this much math during the game was 4th edition, and at least all that was at the end. There are too many things that need to be kept track of and they all slow the game down for a limited benefit.
I'd like to see most army-wide turn-progressive rules (Battle Tactics, Doom and Dread, Power from Pain, and so on) be eliminated. I'd like to see stratagems curtailed to 1 stratagem per unit or something (and maybe one for your sub-faction). I'd like to see scoring be simplified by a lot, too. You do something, you get 1 VP--there, that's it.
5) Smaller Armies as Standard
Remember when 8th started and GW was like "we're making the game more accessible by shrinking the size of armies" and then everyone was like "Well, then let's just play 2000 points!" and then GW was like "Yeah, sure, okay." Enough with the lunacy. For long ages it was clear that 40k was only a remotely balanced game when points were relatively constrained (generally 1500 or less) and that the more amphetamine parrot you could dump on the table, the more broken everything would inevitably be.
This is less of an edition fix than it is a culture fix and, as such, I realize this is probably unfixable, but I stand by that a lot of the nonsense going on in 40k these days is simply by virtue of the fact that armies are so damned large. This has always been the case (remember 'Ard Boyz? :shudder:), but GW is clearly aiding and abetting it at this point, and I think the game (as a game) has suffered for it.
Now, I fully realize a lot of the above is me being a grouchy old cuss and saying "things were better in my day" and so on, but I really DO think a lot of previous editions were superior gaming experiences to the current one, and CERTAINLY a lot more accessible to new players.
Anyway, I'm curious to hear your thoughts about what could be fixed. Have at it!