So where do you stand on this? Oh wielder of the Hammer of Bans.
I think Bethy makes a good point. Bethesda's work and time isn't free. I'm sure there are a million things they'd like to add, but have to cut corners to be able to keep a realistic time table and stay within budget. A modder's time is free (at least from Bethesda's point of view), so they can fiddle and tweak and come up with the greatest things in their own time to add to the game.
Thinking the release of the modding tools is a way for Bethesda to be lazy about what they do, seems rather cynical to me. But, I can see why they would think so, especially if you see the quality of some of the mods out there. I would argue that maybe it's more a way of Bethesda saying, hey look, within the constraints we placed upon ourselves this game is the best we could do. If you want to do it better or differently, here you go and knock yourself out.
In the spirit of the argument of the OP; if Bethesda really wanted to get away with 'less', then for TES VI they could just release the modding tools and be done with it.