What are some of your favorite examples of bands that morphed over time, changing their name, sound, and some of their members? And do you feel the changes were for the better or for the worse?
My example:
Seventeen 
--> The Alarm 
(
The Alarm - Wikipedia, the free encyclopedia )
The band Seventeen was a four-man power pop mod band that released two songs between 1978 - 1980. I feel those songs were very catchy, although lyrically repetitive and simple, but I still like them quite a bit.
Seventeen - "Bank Holiday" (1980)
Catchy with nice guitar work, this song is simple and straightforward and reminds me of songs by the early Beatles, but it is more punkish, which appeals to me. (I am currently addicted to this song.)
Seventeen - "Don't Let Go"
The band's other song was also catchy, simple, and energetic. Nice!
...but then in 1981 the band changed its name, first to Alarm Alarm, and then just to The Alarm, shifting some members as well, and went on to a fair amount of success as an alternative/new wave band, but I was very disappointed by their music and wish they'd just stayed like they were when they were Seventeen.
The Alarm - "Shout to The Devil" (1981)
Boring and screechy, this song reminds me of songs by Robert Plant that I don't like. It sounds like generic '80s rock music to me.
The Alarm - "Sixty-Eight Guns"
An okay song but it doesn't appeal to me much. It drags on and has a lot of emotional screechy shouting.