I see your point, though I have to admit that the philosophical aspects of the Ultima games tend to set them somewhat apart from virtually any other series out there.
I think the philosophy of the U4 games peaked in U4 but after that the system completely fell apart. U5 took U4 to it's conclusion, but the more I think about it, U4 was an aberration. The philosophy in it was outstanding, but after that, everything else is a letdown.
U6 was interesting in the story, and asked the Avatar to do some things in an avatar like manner, but kind of had the virtues as a backstory. They had the Gargish Virtues, but they felt like a rip-off of the original 8 (Feeling? really?) Ultima 7 really didn't have much at all to do with the virtues, but just that they were being replaced by a new religion. SI had the Ophidian Virtues or whatever, but again, would it fucking kill them to make honesty a virtue for serpent people? Why do they have to call it ethicallity or whatever? (Jesus, I'm a nerd.)
Ultima 8 and 9... didn't do anything for the series philosophy, neither did UW1&2, UO, or whatever. The virtues were reference points, but didn't have anything more to do with the story. U9 did a ham handed job of using the virtues to tie an otherwise unrelated game to the Ultima series, and that's about it. In it's defense, at least U8 doesn't even bother.
I think RG's whole philosophy on life is working for him, but he was a guy with a good idea 30 years ago and it defined the series we have today. His more recent philosophical musings really blow, however.