So I started with maxing out Transmutation, to give me a bit of a weapon damage buff early game, but I now feel this was a mistake.
Having brought Str. and Dex. up to the desired numbers first, Int. is still relatively low, so elemental conversion doesn't do much for the total damage output, while late game, weapon damage is going to pale in comparison to casted damage anyway.
It might be better to leave Transmutation at zero points, which might actually help against some bosses: if they're not immune to Freezing Blast, the -100% physical resist means they at least take some damage from weapon attacks. Those six points could go towards maxing Rune of Life for a vitality and bleeding resist buff.