It seems you missed the point This game is not a single player game with heavy emphasis on lore or story. It's a fast paced action multiplayer game. I doubt there will be a lot of immersion and what little immersion there is will be compromised by the players themselves If you expect something else you're going to get really really disappointed
Everything that the devs have control over changing should be as close to the lore as possible. I know there will be people that do dumb stuff, but I can ignore that because it is a game. What I cant ignore is a game mechanic or story element that goes against the lore for little to no reason.
I expect it'll be as close to lore like in all the other big Warhammer games i.e they'll probably hit all the important notes, but if they need to make smaller adjustments in order to facilitate gameplay they will. Personally I had no problem enjoying the Dawn of War games or Space Marine even if they broke lore here and there and I doubt Eternal Crusade will bother me if it breaks it in a small way here and there as well
I say stick to the lore as much as possible. After all I believe its the vast and complicated storyline that makes 40K so popular. Sticking to the lore doesn't mean that gameplay will suffer.
I find it funny whenever the topic of staying "true to the lore" comes up in many forums such as these because 40k lore is flexible to a point to allow an author or game studio to be able to tell the best story they can. It changes from medium to medium, from book to book, and from author to author. That's why nobody is quite sure how fast a bolter fires or just how powerful a bolter round is, but I know the real answer: Bolters fire exactly as fast and do exactly as much damage as the story needs to be entertaining.
Having grown up with paper+dice games (D&D), moved to and through tabletop games (Warhammer and Warhammer 40K) with a changing group of friends and players I have seen over time that "rules" are really guidelines, canon/lore must be prepared to change to suit the players. The object of any and all gaming is the pursuit of entertainment by the players. My stance is this, if lore needs to bend to facilitate the games mechanics then so be it.
Faction lore should be accurate with certain bonuses to certain race and sub faction. But game play it has to be balanced or else ill be reviving the good old days of defending a keep alone in warhammer online vs a hug zerg of chaos players. Factions needs to be balanced. Because the influx of new players that dont care about the lore will join the strongest faction for free xp rewards etc. Like vanuu in planeside 2.
as close as possible but needs to be fun so in terms of gameplay some changes will be needed on the topic of terminator suits make them a high level unlock and give them some disadvantages like big slow target and lack of precision long range keep them close mid range powerhouses some players wouldnt want to give up the maneuverability but others would enjoy wrecking house up close p.s. when i say slow i dont mean snail slow i mean 75% of tactical marine speed
