have you used a storm gust? jupitel thunder? meteor storm? etc....
Yup... with sacrament and DEX you can reduce 92% of the cast time even more if you put more points on DEX... but yeah, having to depend on other classes for cast time makes it harder to go and solo.
We all know that Mage/Wiz classes are the ones who pay for the whole renewal thing... but other than that, Cast Times as whole is working as intended.