It is all very different but change is good...right?
I always thought that the runes and masteries were a bit odd. The fact that you had to spend months grinding to get a decent page of runes and all the masteries seemed unfair to newer players. This new system is certainly a level playing field in that respect.
I don't mind having to grind for longer to get champions. When you buy a new champion you are going to spend some time playing it and getting used to the mechanics etc.
While you are doing that you are gaining XP which will work towards levelling up and buying the next champion. So it all works out fine in the end.
I find the new changes refreshing and long overdue. In no time, we will all be used to them and won't be bothered about the difference to the old system.
You still get a fully functioning game for nothing, so all is good!