Skill based character development has been a defining aspect to the ES series. Bethesda has traditionally done a great job with this method of character development and this is one of the reasons I have always looked forward to playing any Elders Scrolls game. This change alone could be a deal breaker, as skill based character progression is one of the more significant, and positive, distinctions Elder Scrolls 'could' bring into a mmo market that has refined much of the gameplay into a formulaic and repetitive experience.
Citing Ultima Online as an example, a skill based system is doable, fun, and could be popular if given a chance. I know UO did this as well as the prior ES games in that I felt more of a connection to the characters I played since I basically tailored them exactly as I wanted to play them. Uniqueness can go a long way. I don't want to feel like just another Lvl 85 Orc Warrior. And if ESO wants my characters to be like just another Lvl 85 Orc warrior
Also, I won't play it just because it's *Elder Scrolls*, even though I love the series. I love Star Wars but decided to stay out of the Old Republic ( However, I did like SW: Galaxies). Nowadays, I'm feeling as though scrapping ES's traditional skill based system for a character class system is Bethesda's way of showing me that I'm blatantly being viewed as a cash cow, and that saddens me.
TL/DR: Skill based character progression defines the Elder Scroll series
Skill based character progression can work in mmos
Bethesda has been awesome in holding the banner flag for so long on skill based character progression in rpgs but a change in that for the sake of doing an MMO and Elder Scrolls basically loses its soul.