It's a reasonable reaction. I don't mind forking out for substantial content (assuming it's only like £5-10) but it is contrary to what has been said.
Sounds like the new campaign may have more map/layout variety. It's something you get a little of in the first mission, but be interested to see how prominent it is in the Pathogen missions.
Interesting to hear that Alphatech is being brought into it now. That's a deep-cup I like. I had to look that one up as I couldn't remember it from Dark Horse's Colonial Marines.
Not sure I like the idea of the Alien mutated Neomorphs though. We've only really seen it in Fire and Stone, otherwise I don't think it's been a thing in other lore like Into Charybdis. Will have to see how it comes across.