Adding to what @Dybuk already said...
It depends on what you want ur character to bed good at. If you are interested in spell casting (of magic schools) set int to ten, if you want ur character to be good at spell casting (of magic schools) set it higher.
If you don´t care at all about them magic schools, just put it down to six.
The slower learning then won´t really matter because you will have a lot less skills to learn which matter to you (because while there are a lot of magic schools there is only ~1 for every "physical class" (ranger, rogue, tank, bersi....). You will then gladly take a bit more dmg / crit / evasion / defense instead of that increased learning speed
E.g. if you want to go into the hand combat school the main stats are dex and str; now if you want ur character to actually be a bit versatile you then have two choices
- go with int and add some spells to ur only good at hand combat character
- go with some other stat which will enable you to have bonis in other schools as well; e.g. take perception for the assassionation and marksman schools (dex and perception)
Compared to int perception will then increase ur crit, which will help you with ur hand combat style, as well as some other benefits.
It all depends on what you want your character to be good at