I would have to rate the combat (all forms) in this order from best to worst: G2, G3, G1.
The reason being, the control improvements in G2 over G1 were very significant IMHO. I think G2 was therefore the pinnacle. G1 combat just seemed difficult for me to master, and although I managed, I found the strafing movements to be awkward - Again, something G2 corrected. I rate G3 over G1, mainly because of the added features like dual wielding, use of shields, and the revamped archery system. G3's melee combat definitely leaves a lot to be desired, but I don't think it's a totall regression, especially if they get it patched enough.