So I was just looking at my wizard spell cast times (detrimental, specifically ether flame, corona flare and ancient: core fire) and noticed that cast time buffs, like True Devotion and Academic's Intellect (click effect from Frozen Academic's Robe) didn't seem to be affecting cast times at all. For example, with Ether Flame, when I inspected the spell, the cast time showed as "6.0 sec (3.0 sec)" indicating that the base casting time of 6 seconds had been reduced to 3 seconds with items, AA's and buffs. I timed the spell cast time with a stopwatch and it seemed to be about 3.2 seconds(consistently), close enough I guess. This inspection (3.0) and cast time (I timed it at 3.2) of Ether Flame remained the same whether I had the aforementioned cast time buffs or not.
I thought that maybe there was a detrimental cast time reduction cap with items and AA which I had already reached, so now, without any buffs, I removed all of my items (the best detrimental cast time reduction item that I had on this character was Bulwark of Shimmering Order, True Quickening with 40% reduction). It should be noted that without buffs, a reduction of 50% would be accurate for this character, as the only AA that this character has which reduces detrimental cast times (all that wizards get, I think) is Quick Damage, which reduces by 10% at rank 3. So, with True Quickening and Quick Damage, this character should have had a total reduction of 50% without buffs.
However, after taking all my items off to be sure, my naked wizard still casted Ether flame with a 3.2 second casting time (3.0 on inspection), remaining exactly the same even though now it should have a maximum of 10% reduction (should be 5.4 seconds) from only Quick Damage.
I tried zoning and casting outside of the hidden forest and the spell cast time and spell inspection remained the same. I even removed all my items, buffs, zoned to crushbone, camped and came back and the spell inspection and cast time remained the same. RIP the two orc centurions who died for science.