you can filter the Dopesheet so that it only shows you a certain type of keyframes, but this doesn't prevent you from accidentally placing keyframes on other attributes:
The good thing is that if you place accidentally too many keyframes, you can always use the Clean Up button when you select an animation from the tree:
I'm not sure the feature you're proposing is actually necessary, as you could simply disable autokey and key only the wanted changes, or not use tools you don't want to keyframe.
