Elementalist Lux takes way too many spell hits to change form currently
I was playing a PBE game to test the new skin against bots and see different forms. Needless to say it took a while to get enough to actually change the model.
Link to a screenshot of my progress
Some important notes for the screenshot that shows how long it takes - I had already achieved the first elemental form. I have 31 kills against the bots and am at 99%. Let's be generous and assume I only had to hit every bot with two spells to kill them (I definitely had to hit sometimes up to 3 or 4 spells to kill the bots at the beginning of the match). 31 kills x 2 spells each (keep in mind I'm at 99%) = hitting 63 spells roughly to achieve the second elemental form. Against bots, where it was as easy as walking up to them to hit a spell. There were multiple times where I hit them all with the same 2 spells. Needless to say that's a little too much for the skin to need for the second form, at least.
Now, as I said, this was against bots, so my calculations may be a bit off (spells may count for more against human opponents, or I might have gotten too many kills or something crazy), but it's a safe and logical conclusion.