0.978's changes are based partly on old feedback, i.e. they've been wanting to change some things around for these heros for a while but never could get around to doing so because they were limited without the current damage/buff systems in place. For example, feedback regarding Mokou's egg skill was that nobody leveled it beyond level 2, and level 2 of that skill was generally gotten asap, making it a prime candidate for an innate skill instead. Cirno was just plain boring to play with all those passives. Mokou in particular is a weird character because she sounds very powerful in theory, but is sorely lacking in any serious game. So they want to use this chance to make her more useful.
I don't think they purposefully make these changes to make the game resemble LoL, but they're not going to rescind any of these just because they make the game resemble LoL either. Mokou's egg skill isn't automatically activated on death mind you, but seeing how she has an overarching Phoenix theme, and that LoL character is called a cryosumsuchphoenix, I wouldn't be surprised if there were similarities. I imagine at some point in time, having similar ideas between such fantasy games is a given - Harry Potter and the Lord of the Rings both have a tonne in common too...