Regardless of whether he was influential or not, in my mind his music is B-rate. He'll never match a Beethoven, Mozart, Chopin, Puccini, Grieg, Mahler, Bach. I judge music based on how it sounds to me, not whether a composer is considered influential by a certain number of people.
I've heard of and heard all of the pieces (except Don Juan Fantasy and the Tannhauser Overture - I'll look into them when I get a chance) you mentioned. All very nice, I agree. But not what they would have been had a better composer handled them.
The professor was just a guy I had back in first year. Different from the rules guy.

The rules guy was a teacher I had in high school... an english teacher actually. Nice guy. He had some memorable moments. We used to talk a lot about music, etc... I must have been one of the only people in the school who enjoyed classical music (well.... openly), so we got along pretty well. I remember when the two of us stood up during Handel's Hallelujah Chorus and everyone thought we were supposed to leave the auditorium!! IT was funny as all hell... people were so confused as to why we were standing. Good times.
Anyway.... not sure why I told you that story, but hopefully you enjoyed it anyway.