Because of multiple reasons: 1. It's cool 2. Carbine seems to love a ''fair share'' (3 tanks/3 healers 6dps) now atm they got 2 melee 2 range + rifle would make it 2 melee 3 range, going on with the trend would leave it to 3 melee 3 range. 3. We've seen NPC melee casters, so there is a chance (even if it's a small one) that we can play as 1 aswell. 4. We've already got 2 melee ''psysical damage types'' (warrior and stalker), a melee ''magic damage type'' would be the most ''unique'' choice. 5. People just want a melee'ish caster. I think these are the main reasons people want to believe there will be a melee/staff/caster class in-game.