When should a change in singer mean a change in band name?

This is a fascinating topic to me and one that I hope will spark some comments.  When should a change in singer mean a change in band name?

Arguments can certainly be made on both sides.  You might say that the identity of a band is largely determined by the lead singer.  That his/her voice is one of the major defining characteristics of the band.  That his/her personality is what fuels the band and draws the audience in.  Often the singer is also a principle songwriter.  Can you imagine the Rolling Stones carrying on without Mick Jagger?  Aerosmith without Steven Tyler?  And what is the Dave Matthews Band without Dave Matthews? Or Otep without Otep Shamaya?  I don't think so.

The other side of the coin is that a band is much more than just one person.  The creativity, the musicianship, the sound is more than just the fronting member.  Many bands have carried on without their founding or most identifiable front person, and some of them quite successfully.  Black Sabbath was quite successful under Ozzy Osbourne and Ronnie James Dio, and even survived with Glen Hughes.  Van Halen was dominant with both Sammy Hagar and David Lee Roth.  Genesis with Peter Gabriel and Phil Collins.  AC/DC has probably the most longevity with Bon Scott survived by Brian Johnson.   More recently, Journey made a huge comeback with Arnel Pineda after being most successful with Steve Perry. 

This question was brought to the forefront of my mind with the recent news that Sick Puppies frontman and founding member, Shim, was leaving the band.  He also claimed on social media that he was dumped without a face-to-face before the other two members announced it online.  Regardless of how or why this came about, fans are all up in arms and seem divided about what the future of the band will be.  I tend to think that Shim was an integral part of their songwriting, sound, and stage presence.  It is hard for me to envision them carrying on similarly without him.  Although, I know that bassist Emma has also written some of their better songs and she is extremely popular as well.  Only time will tell in this instance.

Many modern metal bands have gone through changes in lead singer and the results have been mixed.  In the genre of music where loyalty means a lot, some fans will never think of a band the same when members change.  Other times it takes the band to new heights.  The following are a short list of metal bands I can think of that have made changes to their singer:

Drowning Pool - Original singer Dave Williams died after touring extensively on their first album.  He was replaced by Jason Jones for one album,  Ryan McCombs for two albums, and then Jasen Moreno.  The band was never as successful as with Dave.  I think part of this is the songwriting, but part of it is that Dave was such an enigmatic front man and the memory of his untimely passing at the height of their success was hard to overcome.

Evan's Blue - Kevin Matisyn was a founding member in 2005, came up with the band name and added a unique singing style to their first two albums.  After disagreements with band members he was ousted and eventually replaced with Dan Chandler in 2009.  The band continued through two more albums and had moderate success.  I thought the band name should have changed because Kevin's sound was just so different.  The band is currently on hiatus.

Flyleaf - Lacey Sturm (Mosley) recorded three ripping albums and was an unbelievable performer on stage.  She left amicably and was replaced by Kristen May for the fourth album.  Kristen is not bad, but in my opinion, Lacey was the sound of the band and Kristen is so much more pop sounding that they should not even have the Flyleaf name.

ill Nino - Jorge Rosado was the original singer from 1998-1999.  When he left, bassist Christian Machado moved to lead vocals where he remains.  Some fans thought the band lost some of their rawness and agression with this move.  I only started getting into ill Nino shortly after the switch and I think Christian is a talented frontman.  He also has some of that lead singer cockiness too and I think he has added to the band in his newer role.  Seven albums later they are still putting out great music.

Soil - Original singer Ryan McCombs played on three records, was replaced by AJ Cavalier for two albums while he played with Drowning Pool, and then Ryan returned for the newest effort.  AJ did a decent job filling in, but in my opinion Ryan belongs with Soil and Dave is the only singer for Drowning Pool.