Wow you really don't notice all the subtle differences until staring at both side by side and doing some ps work.
The original Yoda seemed to always have a natural smirk, his forehead ridges were more pronounced, his head shape was narrower and his eyes were much bigger.
I happen to love both. I think PT Yoda fits fine (and will work even better when TpM version is replaced) and the OT Yoda works great as well. The most that should be done to the OT version is little mouth and eye movements like AdY is doing for EsBR. Just minor tweaks here and there.