Hello, just wanted to input some of my own thoughts on the matter. I'm sure a lot of what I am thinking has already been said but I figure it couldn't hurt to say it again.
I'm still relatively new to LoL, so I personally experienced the want of a familiar champion or two in my first weeks. Every week there were new champs that I had no idea how to play. I'm also really new to gaming, this is the first game I have ever played more than the initial set up of my account. This makes me completely lost in remembering which champs are what. I would just find out that I've been playing a tank as an ad and it'd be taken away and replaced with who knows what.
Now that I've bought a few champions, I also see the appeal of trying to test as many champions as you can to see whether or not you like them before you spend all your ip on a champion you won't enjoy playing, especially the higher priced champs.
Since Zyra came out and now Diana is coming, I've been really excited, so I'm very interested in what people are saying about free playing them as soon as possible. I don't think it's realistic for it to be the first week they come out, to my understanding this happened once and worked out, but it kind of deflates the release if you know everyone will have them for the first week. I think Riot Games should consider letting at least the first week, possibly two, be exclusive to those that purchase the champs. After that I know the rest of us would love to see them in the next week's rotation so we could test them for ourselves.
I really hope this idea is considered and possibly put into motion. Thanks for the time, Riot Games you're doing great, keep up the good work!