I'd say that Blast and Penetrating Blast are a must for ranged wizard with decent MIG/DEX/INT. Just make sure to not equip Rods (because they are slower than wands and sceptres; unless it's Golden Gaze which fires two projectiles at once). The thing is that such a wizard can easily compete with a barbarian in party in terms of total damage done (until the last one gets HoF).
Penetrating Blast is probably unworthy only on cc wizard with completely dumped Might. Such wizzy could either wield 1h+shield (and thus no blasts at all) or go for Gyrd Háewanes Sténes or Rod of Pale Shades, and passively dominate/stun stuff.
Thanks for the input. The wizard being Aloth, wich he already had blast, I thought it would make sense to upgrade his ability. I pefer using wand and scepter also with him. I also want Aloth to have some CC and some magical damage so I'm trying to mix both, so far so good as the game progress. I like his damage spells. (normal difficulty)
It's just that there are so many talents, it's hard for me to make a decision considering I will probably play the game only 1 playtrought because I do not have the time to play more, so I'm trying to make the best out of my decisions.