I don\'t know many other RPGs. Especially no other MMORPGs.
And in my opinion, it is just the opposite: It takes ages to cast a defensive spell, and to cast \"Weakness\", you must be so close to the enemy that you will get hit if it is a chasing one.
Apart from that: At the moment, spells are so weak that you need to cast them more often to get decent results. And the main drawback: You must not move while casting a spell! If you move, the spell will be aborted. You cannot fight back with weapons while the spell is being casted.
Another limiting piece is the reliability. I cannot recommend to cast a spell with more than 20 to 30 % of power. Beyond this, the casting gets so unreliable that it is not even worth spending mana in several tries, compared to the little bit more effect.
So you see: Depending on the experience you have, the conclusions are very different. In my opinion, at the moment you may not need to learn any spell. The only exception are attack spells like Missle or Fire Blast at high levels. Because high skill only seems to reduce the mana consumption, but does not change the reliability or the power or the casting speed, as far as I see.