IMO something to consider is the intended audience. For example, Space Marine was in no way a truly innovative game, because it was going to be released on console. In this same way, SH:DW and the survival of the studio likely depends on the success of the console sales of EE as well.
So I wonder which we would prefer? Adequate games - because to me, SHDW was in no way a "terrible game" on the level of Eternal Crusade or DoW III - with the studio enjoying enough success that they may be able to one day do something truly experimental, or more purely experimental games that are most likely to be failures? Because it's not like BG:A was a more complex game than SHDW to develop - it was going to run only on PC from the start, it doesn't need to worry about making complex geometric renders instantly like a FPS does, latency for multiplayer is obviously way more of an issue in an FPS than for a comparatively slow-paced (but obviously still very time-sensitive) game like BGA.
I think it's closer to L4D than Doom
Yes, but I feel that influencing that are a couple considerations:
1) It does not have a third-person mode
2) terminators in a cramped space could not control as freely as unarmored humans
3) You're supposed to feel like you're in a confined area - a space hulk - rather than meandering through the woods and the open streets of a major city
Consider that, and SOME of the design decisions make more sense. Keep in mind that they were also keeping the fan base of the original Space Hulk games in mind with stuff like locking doors behind you. They were trying to make a WH40K Space Hulk game. NOT WH40K: Terminators on the Loose , NOT WH40K: Siege of Terra , NOT WH40K: Eldar High School Light Novel.
Looking at it as a WH40K: Space Hulk game, it does not excuse the design "flaws" like repetition (because AGAIN in Space Hulk you do NOTHING but the same thing over and over it's doors and genestealers.) but it makes them more understandable.
I guess this is subjective, because I sure as fuck felt like they controlled like terminators. A space marine can't fire a stormbolter or use a thunder hammer one-handed, nor could they parry a Broodlord's melee attacks. Speaking of which, the melee attacks felt heavy and powerful as fuck to me, too. I guess this may be why I enjoy the game more than you do - I feel they termies are as slow and heavy as they should be. Comparing directly to Space Marine's movement speed, you are snails - even though, of course, termies are SUPPOSED to be way faster lore-wise.