Well it should be an interesting year. The last of the 9th edition codexes are due out soon - that would be the plainclothes edition of the Imperial Guard (I picked up the fancy horse edition already) and the World Eaters standalone book and maybe Space Marines 9E 2.0 though those rumors seem to have gotten fuzzier as time has gone by.
I have to say I have liked 9th edition. I thought it showed an effort to add a lot of flavor back into the game in individual codexes plus the one-volume set of rules for the Forgeworld units was an incredibly player-friendly move. It really felt like GW was paying attention to what was happening in the game as we went along rather than just pumping out a pre-planned set of new material. It wasn't perfect but it felt like a serious effort was being made.
The irony is that almost as soon as the game is "complete" - in the sense that all factions have a new codex - we are going to reset the whole thing and do it all over again because every indication is that 10th edition is kicking off this summer ... sigh. Wouldn't it be cool if GW spent a year or two cranking out all of the new army books and then spent a full year just doing some campaign books like Vigilus or Charadron or Arks of Omen? A full year where all of the factions had been updated and we just rode with that with some extra optional material and some mission packs? I think it would be damn strong and make a lot of people very happy but business is business I suppose.
Tenth edition of the game ... well there's a mixed-feelings milestone. I started with 1st edition or "RT" as people call it because I had been playing Warhammer fantasy for several years already and thought "fantasy races with sci-fi gear" sounded like a lot of fun - turns out I was right! Heck my kids started playing during 5th edition ... time flies ... especially when they reset the game every 3 years.
It sounds like we're going to get the remaining daemon primarchs added to the game. It's weird to hear people talk about Angron and Fulgrim like they're these great unknowns when I was playing with them in Epic 30 years ago. Sure, they worked a lot like a greater daemon in those rules but they had their own abilities and their own models and we used them a lot in our battles. It will be cool to finally see them in a bigger scale with modern design capabilities. We've come a long way from when a 40K army was 20-30 guys, a dreadnought, and a landspeeder or a mole mortar.
I am still happy with 40K. I liked the big reset system-wise with 8th, I have liked most of 9th, and I am looking forward to 10th. Hopefully they keep getting it right most of the time.
For 9th my "new edition new army" was Necrons even if I came to them a bit late. Now they are finally approaching a "done" status - for the first wave at least. It's been a thing for a long time. For 5th I got my marines and orks into usable shape as the boys got interested. With 6th it was refiguring the Chaos Marines and starting up some Dark Angels. For 7th I updated my Eldar and got them into a coherent force. For 8th it was reworking the Blood Angel pieces I had and making them an actual usable army. I also split my Death Guard off into a usable solo force. Rumors are that the new edition boxed set will feature Marines vs. Tyranids and if that's true then I suppose 'Nids will be my new army for this edition.
So yes, it should be fun. Finishing out an edition I liked and starting up with a new one will definitely keep things interesting this year.