Actually I never found that high levels of blaster skill made a lot of difference. It makes you more likely to hit, but with Hour of Power (even Haste lasts more than a day at high Light magic level) your bonus to hit is so high that you are almost certain to hit anyway.I use rapid-fire shrapmetals when fighting the dragons in the Arena (using that I can kill the 20 dragons in less than a minute), and in the big room in the Hive when you enter. The rest of the time, yes I just use the blasters...
--Chandor