Would go for magblade. Good dps, ranged, self healing and a good sustain, I'm currently levelling one on my own as well. Keep in mind though that if you're going for pve damage, magblade requires more practise to master compared to templar and sorcerer. Personally also find a magblade much more fun then a sorcerer, but others may disagree with me on this.

MagDk currently has sustain issues, and probably especially in solo play. Magwarden can be fun but is relatively weak and would fit a role as healer better currently. Then once again, looking at self support, damage, sustain, and the advantage of ranged builds, go magblade.