Ok I need some help. I want opinions on regimental creation. Should the GM come up with a regiment from scratch to fit their campaign, or let the PCs come up with a regiment on they're own as a group? Which way works better? Any input would be very helpful. Thanks.

Well so far my group was making there own but they kept bickering, so they're picking a Homeworld from one of the regiments in the the CRB and HotE and the regiment type and I determine the rest which has been A LOT smoother, kind of gives the best of both worlds, they get established lore to go off as for as origins while making their own regiment (Vostroyan Guerrilla regiment now)

I haven't started our group's character creation, but I've created six regiments for them to choose from, all variations on the infantry theme

We let the players decide in my group.

What if the players don't want to be mechanized for instance? Would you then shoe-horn them into something armoured regardless?

Obviously the players should work with the GM on this so both "sides" can enjoy the sessions, but the GM's campaign shouldn't be so strict as to not allow different regimental types to exist across that given threater of war.

I think its important for a back and forth on the matter.

In a previous game I ran, I let the players have mostly a free run of their choices, but I expressly forbade the use of any regiment type with a vehicle (vehicles didn't fit the scale of the game I was running). I offered suggestions, and helped play up the background of the unit while the players bounced ideas around. When the players were having trouble with specialist equipment doctrines, I jumped in with a solution. The players had a hard time choosing between siege and line infantry. They went with line infantry. They had 3 points at the end, but couldn't decide on a preferred equipment doctrine, I offered to use those points to add the "difference" in items between siege and line infantry to their standard kit.

My next game I have planned though, I might end up defining a bit more of the regiment on my own. I've run this by all my players and they are open to me creating the regiment. The reasons are twofold:

1. I want to try out the mounted combat rules in HotE. This inherently forces the regiment into certain decisions.
2. While we did come up with an interesting regiment making it as a group, it lacked quite a bit of flavour. It essentially had no history, no background. It existed in a vacuum (as it was created shortly before start of play, and otherwise had little to do with the campaign I had created at large).

I agree that the choice of a regiment is something that should involve everyone. The regiment is a huge part of the characters' backgrounds - indeed, it is almost as important as the class selection - and if you want the players to enjoy the game, they should like whatever they end up representing. I'm not even talking just about game mechanics or advantages and disadvantages … there's a huge variety in style, both visual and cultural, that would greatly affect how the characters in the squad would have to be played, and I would expect most players to lean strongly towards certain directions, be it because of something they've read in 40k, or because it reflects their thoughts and preferences about various real world armies that ended up inspiring the 40k regiment's design.

Needless to say, many groups will probably feature different opinions, but I would hope that a compromise that allows everyone to have fun with the regiment is just a matter of time.

unless it is vital to the campaign that the players be from a specific regiment or be from a regiment with particuler specialites (example death korps= seige specialists, catachan= jungle warfare specialist, attillans= rough riders, etc) then it should fall to the players to choose what regiment they are from.