IIRC, Morello actually made a post about just. Near the start, they had the same philosophy as Dota, that is, every skill-cast should have to be carefully considered, except in a few rare cases (ex. Lion or PA); Over time, their philosophy has changed to more "What skill needs to be gated through a high cost?", for example, Shen's dash has a massive cost, where as his Q is rather low cost. Meanwhile, the one skill Darius has that has a cost he needs to consider is his R, or his whole QEW combo together. While it's fine for him to spin for days, if he wants to go all in he should have to carefully consider it.
It's a very interesting take on things, if not necessarily one I agree with.
http://na.leagueoflegends.com/en/news/game-updates/patch/patch-45-notesOn another note, 4.5 notes are out. I'm oddly pleased with this patch. Gragas players will cry for certain, but whatever, I'm tired of seeing him played 24/7. As a Rengar main, his rework doesn't initially piss me off, so it's just a matter of how the numbers feel. All of the balance changes seem reasonable. I look forward to Feral Flare, it could be really awesome. Wriggles might finally be good again!
Only things I'm not sure about are the runes and Miss Fortune. The runes mostly because I don't have CDR runes yet so that's gonna be hella expensive. MF's stuff looks like mostly a buff, but looks can definitely be deceiving.