Moved to the correct subforum.
By more rooms, I'm assuming you mean larger map generation rather than more room variation? I personally feel like a larger map would result in most of the game feeling like padding, I think the currently generated maps strike a fine balance between exploration and navigation. If the facility truely felt like a maze, then there would hardly feel like a progression aside from the different zones, and traversing with stamina that operates in fairly short bursts would feel like a chore. On the flipside, if the facility was small and compact, you would be able to easily mentally map where to go and be able to navigate to the next segment of the game with little trouble. As it is now, a lot is left to exploration, and it is easy to get lost, but there are plenty of landmarks and hub areas you can use to right yourself. If the game consisted mostly of long stretches of corridors interconnected with each other with a unique room once every blue moon, it really would feel less like a facility and more like what it is, a bunch of tile pieces laid together. As for it not feeling like an expansive facility, most of what the player traverses is only a small portion of the facility, there's inaccessible walkways, unreachable doors and distant windows scattered all about. Just because it's not seen, it doesn't mean it's not there.
As mentioned above, you could just create a much larger map through the creator, though that defeats the maze-like quality a bit if you're designing it beforehand.
holy smokes i did not mean to type that much out