Just ringing in here haha
I am a huge WICKED fan...not ashamed to say it. While I do find the leading girls and Fiyero's song more appeasing to me personally (Elphaba mostly) I do think the Wizard's songs are pretty good.
Now, "Sentimental Man" is a song I wish they would spice up a bit and add a bit more dialog before (I dont like how it almost jumps right into the song) and by spice I do not mean "belt the face off" but I think they should add more of a melody for it. However I do find it to serve a purpose. IMO, the Wizard is not the main villian of the show. He is mostly a puppet to Madame Morrible and his lust for power. Yet deep down he does have a conscious..and this song displays that. While he is trying to have Elphaba fall under his spell during this song, I think a part of him really does want to be a father (as displayed towards the end of the show.) I think if they added some lines before hand (maybe Elphaba explaining what her goals are and what is going on in Oz) and some more melodic structure the song would be much better.
"Wonderful" is a song that I'm shocked a lot of people on here dislike. I find it to be quite brilliant. The score of WICKED has a very other worldly aspect to it with a lot of songs built in disjointed keys I guess is the way to explain it. But here since the Wizard is from our world, his songs do stick out as more of a Vaudeville song. I also think the political undertones are amazing. My history teacher went to see the show and he loved it, and he says this song is amazing at explaining how history can be twisted to influence a general population (aka, Nazi Germany)
Again, this is all my personal opinion.
And to touch a bit on the two leading girls, I find their songs to be amazingly beautiful. The orchestrations I think just bring the audience into the world of Oz, and while many on here hate the lyrics, I find them to be extremely witty and accessible...which is where I think the success of the show is found. People from 8 to 80 can associate themselves with one of the two girls.
"Life in theater is give and take...but you need to be ready to give more then you take..."