Should low INT spellcasters be able to learn one spell per level?

[PowerWyrm]

Let's say I'm starting a half-troll mage and I put all my points into str/dex/con to play like a weak fighter in the beginning. I won't be able to learn any spell if my int is low enough, while still having mana to cast spells because the number of spells per level I can learn is lower than 1. But why should I be restricted by number when mana restriction is enough? Maybe consider setting the lowest number of spells you can learn per level to 1?