The point is simple.
Which, according to you, is the band that has undergone the most changes in style and writing throughout their entire career? From their first CD to the last.
Also, I'm NOT talking about changing members, a band can actually change it's entire line-up and still sound fairly similar to what it used to be.
The example I'm citing here is Dark Moor
Guitar player has remained constant, but the entire line-up went through a lot of changes in the early 2000's which include a vocalist-second guitar-drummer-keyboardist change.
However, even after that change, their style remained intact, it wasn't until they managed to attain a stable line-up that they started to change their style a lot.
Here's a list of their CD's and an example of a song from each
1.- Shadowland (1999)
https://www.youtube.com/watch?v=_rjFqaoy7KM2.- The Hall of Olden Dreams (2000)
https://www.youtube.com/watch?v=yZY9qyuXYgs3.- The Gates of Oblivion (2002)
https://www.youtube.com/watch?v=3ZV7IXpaKKE-This is where pretty much everyone left the band but the guitar and bass player-
4.- The Dark Moor (2003)
https://www.youtube.com/watch?v=XVO5pWPu6O45.- Beyond the sea (2005)
https://www.youtube.com/watch?v=ZrjaBEG69E4-STABLE LINE-UP STARTS HERE-
6.- Tarot (2007)
https://www.youtube.com/watch?v=PZgEfQhSpBY7.- Autumnal (2009)
https://www.youtube.com/watch?v=ZnHPWvAKzPE8.- Ancestral Romance (2010)
https://www.youtube.com/watch?v=iT_zjSVmVjQ9.- Ars Musica (2013)
https://www.youtube.com/watch?v=5pgRvvVCQGU10.- Project X (2015)
https://www.youtube.com/watch?v=UjWoK1IEeYw11.- Origins (2018, upcoming)
https://www.youtube.com/watch?v=VuOFArN15LsSure as hell there are bands that changed a lot more, I'm just sharing this because this is my second favorite band after DT
Still, I'd like to add that this "change" has upset a lot of fans since at least Ancestral Romance. Also, another note, these songs where picked at random, I actually recommend a lot hearing the albums to get a better a idea, but I think this should work just fine.
Please tell me other examples, I'll be reading/listening!