If you want to be a mage, put points into mana. You're a mage, for crying out loud. Mana and vitality, and just enough strength to wear your equipment. And dexterity? Bah...
As far as the question of losing your charms when you change equipment...well, when you start out, you have low quality equipment, and low quality charms to go in the equipment as well. As the game progresses, you find higher quality items that you'll want to start using, but you'll also find better and better charms to use. It's not perfectly balanced, but it shouldn't pose a quandry as to when or when not to use charms. They're meant to augment your stats, not be the sole source of them.
If you wouldn't mind, point me to the posts where you're reading that you should only use charms to gain mana, stamina, etc.. I'd like to know who I'm disputing.
--Flix <img src="/ubbthreads/images/graemlins/cool.gif" alt="" />