Even if d3 pvp becomes somewhat balanced/playable from Blizzard (through slight skills tweaking), don't forget that there will always be 2 camps of gamers. One camp of elitists who definitely will spend hours and hours of practising and eventually become really good - for which 100 paragon is just matter of few weeks and shouldn't be capped. And then more casual players - like 90% of all who take part in duelling, who are pretty solid with paragon lvl 40, 50 for example. So as time goes on, I'm still pretty certain this will need like 2 rulesets ("leagues").
One for more casual audience, which will be even more popular I suppose, and other one for diablo hardcore nolifers.
I mean even in d2 tvt you had no chance to win some veterans while you were just rookie...expecting in d3 even bigger gaps in difference (due to the crazy items etc.)