I do think his recent (well, comparatively recent) adoption of Buddhism has affected the latest incarnations (no pun intended) of Star Wars. Think about all of Yoda's advice to Anakin, about not grieving for your loved ones, steering clear of all emotions/feelings, etc. Make no mistake, I think he drew upon many aspects of many religions in his original conception of the Force, including Buddhism, and that Yoda was intended as a Buddha-like figure right from the get-go, but in the prequels, the 'Jedi Code' and the concept of the Force runs counter to some of the things in the OT.

But is he a Buddhist? I'm not so sure myself these days. His 'midichlorian' explanation of the Force tends to de-mystify it and seeks to give it some kind of scientific basis...

Perhaps more correctly, Lucas' place in life has affected Star Wars. There is, as people have mentioned, Greedo shooting first/at the same time. The Jedi are forbidden to marry (Lucas divorced between ESB and ROTJ). The main characters are no longer ordinary people thrown into extraordinary events; they are people destined to power. Lucas was once an ambitious young director; a small fish in a big pond; a rags to riches story, but perhaps now he believes that he was always destined for greatness...