For casual player i would still recommend Cw, it gives more options tactics then Ap and for me it was more fun.
Rage skills in Legend are with catch, for every rage spirit you need to do something to use them. In Ap/Cw you get pet dragon on start and there is nothing you must do it`s free. So rage skills are easy to use.
There are mass slow, and chain lightning in game. You must upgrade certain magic schools : for mass slow you maus have 3rd lvl or distortion magic skill in mind tree and then upgrade slow spell to 3rd lvl. For chain lightning order magic skill 3rd lvl, it gets chain effect and shock% (make units hit by lightning shocked, and unable to move). Also there is mass haste, mass bless, mass demon/dragon slayer, mass weakness and so on. For stronger spells you have to invest runes to magic skills and upgrade them.
Difficulty on start will be lower on easy lvl, but still mage will have problems because his best traits are high intellect and lots of spells. Both of those are not available early game. But if you manage to get to Verona there should be lots of interesting things there and beyond to make mage class fun to play.
After Demonis you`ll get new quests and have to get back to Elven islands and pass labirinth to orc territory. So you`re around 80% done.
As for mod i recommended in post above, dont go there. It`s made for harder then impossible play and i guess you wont have fun in it. But have it mind in case you want try harder diff settings later (and if you want to have nightmares of enemy heroes destroying your whole army in 2 turns
)