I think you might be thinking "new ways" to play champions means.. Well, more than it does.
As an example, take 
as a jungler.
Used to be, you didn't really have much in the way of options for what masteries you ran on him. You went Thunderlords if you were jungling, Fervor if you were laning / banking on getting fed and turning into a kind of bruiser carry. That's it.
Current runes give him more flexibility.
Shock makes him a super threatening burster, popping out into a gank and almost immediately deleting someone.
PTA allows him to function as more of an enabler. Dangerous early game trasitioning into an off-tank, and then picking fights where you enable your teammates to better kill an important target.
Tempo allows him to still function as bruiser carry, not having to be suicidally squishy while still getting massive amounts of his most important stat.
There are other options even, Glacial Augment (is that what it's called? the slow?) would be absolutely murderous in ganks. Resolve wouldn't be ideal, but has some interesting options if you're the only front liner on your team and you have to play like a true tank.
In all honesty, I don't think Runes Reforged are going to enable bizarre shit like AP Trynd of ADC Leblance. I do, however, believe that the system offers more flexibility for quite a few champions, offering them subtle but powerful differences in how they're played and what strengths they bring to the table.
