Well, in relation to the wizard's talents, I recommend having a passive talent tree that works with all specializations (if you have one), and that this talent tree, you choose a talent at every X levels, like this:
"https://i.ytimg.com/vi/9iZPLNf6Rpk/maxresdefault.jpg"
Regarding the talents of the wizard's specializations, I recommend that you call them mastery! in it, there will be talents that only buff the spells of that specialization, and in this tree of "mastery" will have the active talents unlocked, when the entire previous one is uploaded, like this:
https://static.wikia.nocookie.net/orderandchaosonline/images/5/55/Talent_tree.png/revision/latest?cb=20110506133326
I recommend that the talents of the class are related to usefulness, dps, defense, and survival, and that they are available to all mages, already mastery, will be similar to speciazalições, in which you gain the effects of the class, as your level increases , in mastery, we could have all the passive and active effects when reaching the maximum level, so that at the maximum level the mage’s masters were totally different, I recommend these mastery (specializations), fire, ice, lightning, soul, fire it would be a mastery of constant waves of dps, with explosions every given time, and cooldown burst abilities, with only constant gross damage, more damage. Ice would have fragmentation mechanics to defend the enemy, so as to cause more damage, he would try to keep enemies on top of his ice skills constantly, so as to cause more damage, the ice wizard would be a wizard who doesn’t walk, he would have to stay on the ground constantly to be able to apply the maximum slowness and freezing skills possible to amplify the damage, the electric wizard would be a wizard with high mobility, able to stun the target, thus gaining more damage against stunned targets, the same would be based totally in mobility and constant damage, it would be the best to cause constant area damage, however it would not burst very strong, and it would be more for mobility and area damage, the soul magician, it would be a mage based on controlling effects on the target to expand his damage type, he would have loads of soul, in which he would have to spend a bar of "soul" to use his skills, he would have to keep dps constantly to fill a bar and use a skill more strong, it wouldn’t be made for burst, but it would have a little and mobility, and it would have a lot of survival.