I'm a saga fan and dig on all the movies. So no, I'm glad he kept going.
Still, if Lucas had called it a day back in 1977, I think critics and people generally would look back on ANH with a LOT more fondness. It'd probably be similar to how people think of the Wizard of Oz. In general, I think Star Wars would have a lot more popular catchet. The subsequent films (all of them) diminished that.