I voted for small, moderate, and ability score changes, although (apart from ability scores) the catgories are not all that clearly defined.
I was considering changing the ability scores myself as a houserule, but it was too big a change for me to effect in isolation. However, it serves as a perfect example of the level of changes I think should be made in a fourth edition when it arrives:
The idea was there would be seven ability scores: Strength, Dexterity, Constitution, Intelligence, Intuition, Charisma, Perception. The first three would be considered physical, the next three mental, and Perception would be neither.
Initiative would be based on Charisma and Perception. Melee attacks would be based on Strength and Dex, while ranged attacks would be based on Dex and Perception. Casters would use two different stats for their casting. The idea being to reduce reliance on any one stat.
Similarly, there would be two base saves for each class, physical and mental, and any physical stat can be added to physical (and similarly with mental). Thus there would be six saves in total. The DM might call for a Health save to fight off a disease, or a Charisma save to avoid a charm effect. There would be no saves based on Perception, because the only thing I could think of for it was illusions, and prefer them under intelligence.
Now obviously, I don't expect the next edition to work exactly like this: Hopefully, full time professional game designers can come up with something better than I can. But, it illustrates the idea: Same general principals, but anything goes in the specifics.
glass.