Didn't they though? As you rightly pointed out, there's calculations about this. And these very same calculations show that the GCD is affected in such a tiny way that you'd need literally 100 spell speed to reduce your GCD by 0.1, you know... as I mentioned in my earlier post.
Realistically, you're going to get around 200-250 spell speed out of Selene so that's shaving literally 0.2 seconds off your cast time. In extremely rare cases this might just make the difference between casting or not if you're moving around a lot, but realistically it's going to matter about as much as dyeing your armor and proclaiming that 'red ones hit harder'. In short, there was no conclusive evidence to say 'spell speed is better', just a lot of speculation about best builds. Also, it relied on best-case scenarios rather than any attempt at a real battle.
In either case, the difference was so small in damage between SS and crit builds that you're not going to set the world ablaze with your awesome damage boost.
