In general, mages are typically support players in PVP which can make or break a team. A group of fighters with mage support will always have the advantage over those without it.
However if you want to play solely as a mage and be viable as a solo player against melee characters. You will need to become more familiar with your positioning, cast time, and how to kite when being chased. Mages obviously cannot just stand there and cast on a melee fighter and expect to win the fight. You will need to implement your fast movement to your advantage, while looking for opportunities to cast your spells. Don't forget to throw your corrupts!
This probably comes with time and a lot of practice, watch some mo1 videos of mage play.
Nonetheless if you wish to play as a "wizard" who goes around and killing melee players, I would suggest you wait for mounts to be released, then make a fat mage build who deals high damage while at the same time possessing a large mana pool. Not only will most melee foot fighters try run away from you, but also mounted combat won't know how to deal with your sorcery if you know what you're doing.
In terms of range of casting the spell, I think if it was any more further out it would be unfair. If you want a long range high dmg attack spell, wait for spiritism school to be released so you can cast mental projectiles!
But honestly you don't need all that range if you are chasing people on a mount, or if you're good at chasing on foot.