I seem to remember somebody saying that the problem with quick saving and loading wasn't so much from quicksaving, but rather loading a saved game when you are already in the game and in the same cell or area as the game you are loading. Supposedly, this could result in some of the data from your position before you loaded the next save carrying over into your newly loaded game and then getting saved into your game the next time you save, corrupting it. Granted, this was Fallout 3 but I developed the habit of going back to the main menu any time I decide to go back to a previous save or if I die (to prevent the game from going back to a previous save). It's very rare for me to have corruption issues, and I use auto save and quick save (but never quick load) constantly.
I think this was certainly the case in Oblivion: I noticed that loading a save from the same cell in which it was made (e.g. loading a recently made quicksave) pretty much guaranteed a crash within 1-2 minutes. I haven't noticed this in Skyrim, but that's not to say it never happens. I imagine the same thing could be responsible for the crash-on-save problem, i.e. subsequent saves from stuff that's still cached in memory that the save process hasn't properly reevaluated, perhaps.
I've seen the comment about overwriting saves causing corruption for years now but that hasn't been true since at least Oblivion, if it was ever the case. It's a very persistent one, though; even though there's nothing intrinsically wrong with overwriting the same data (if there was, no database software would ever work, for example.)
Edit: for the record, my saves are now just over 16MB too, after about 150 hours or so of gameplay. Few if any CTDs now; I did have a
lot back when Steam was being loaded and I didn't have the 4GB mod running, but since then, the half-hourly crash has all but gone away.