Rage is a console game that has a 25 GB installation, and is published by Bethesda too. Your arguments are invalid.
Btw, those 25 GB (and the price) are the reason that prevents me from getting that game.
The publishers just sign the paychecks mate. Bethesda Softworks != Bethesda Game Studios. They're part of the same company, yes, but they have two radically different jobs.
Rage was developed by iD software. Brink was developed by Splash Damage. Hunted: The Demon's Forge was developed by inXile Entertainment. All of the above were -paid for- by Bethesda.
The last game that Bethesda developed was Fallout 3, which requires ~7GB. All in all, Bethesda Game Studio is landing in the same target circle they've been consistently hitting with every game they've released this generation.
My wife is looking forward to it but i'm on the fence. I didn't like the way the monsters worked in oblivion, i hated that there weren't any extremely difficult encounters. Part of the fun of RPG's is getting your *** kicked multiple times, having to figure out what your doing wrong and adapting accordingly. We shall see!
From what I've heard, they've fixed that in Skyrim. There will be some places you simply can't go at lower levels because you will be horribly mauled by monsters. They're doing their best to strike a balance between Morrowind (where you could get mauled horribly less than 20 feet from the start location) and Oblivion (you were never mauled horribly).
Here's hoping.