The only requirement is that the class must thematically make sense. Blizz has outwardly stated this.
Every other point is coincidental or mostly untrue.
1. Major Lore Figure: this is the same as expansion theme, and is coincidental and incorrect in a way. Evokers don't technically have a major lore figure, unless they introduce one. There is no evoker class, they were created to fill a role and then sealed away. LK had deathknights, Panda had monks, Legion had demon hunters, the lore figure for each expansion is coincidentally attached to the class.
2. Playable version in MOBA/RTS: weak argument, wow classes are pretty far removed from their RTS and MOBA counterparts, just because it's a different game with different mechanics. Evokers break this as well, there are dragon themed heros in hots but they are just being themselves and using dragon abilities. At this point mostly everything created will just be reskinned abilities from other classes.
3. Landmass: this is just expansion theme again.
4. Abilities that don't fit other classes: this one is the least thought out, if anything Evokers are the first class that has been made specifically stating they can do things other herosmakes. But that isnt going to stip them from feeling like repeats. DKs are magic warriors and take their abilities largely from that concept, with the exception of a few abilities, a lot of their kit could be in other classes kits. Monks: ditto as DK, there are a few very specific themed things like their alcoholism, otherwise their kits could work elsewhere. DHs are literally rogue-demonology spec, with traps from SV hunter. Evokers are going to mostly come off as mouth breathing mages.