IV is probably my second favourite of the series after the first one, I really disliked the second and whilst the third one was ok it only felt like Mission Impossible during the Vatican bits.
My only quibble would be that I felt it peaked in the middle with the Dubai bits, I wasn't that impressed with the car park fight if I'm honest, plus the villain could have had a bit more screen presense.
I wholeheartedly agree with you. The villain was, for the most part, rather insipid and so were his motives. And the entire sequence in India felt pedestrian.