So the following quote means that having two level 100 paragons was a waste =/
Not at all. With the way the system works right now, we'll first start by adding up Paragon experience across all your heroes of specific type. That cumulative experience will then be applied to the new Paragon leveling curve to determine what your Shared Paragon level will be. Depending on how many characters you have and what Paragon levels they are at the time Paragon 2.0 goes live, it's definitely possible that your Shared Paragon level will be above 100 (remember that we're removing the cap on Paragon at the same time). So, a player with 2 or 3 p100 characters will certainly be farther along than, say, a player with only 1 or 0.
(Note that Shared Paragon levels are broken down by game type, though. By this I mean that all of your Normal characters will share a unified Paragon level and all of your Hardcore characters will share a unified Paragon level.)
* In case someone asks, the experience curve for Paragon 2.0 is still under development, so I can't give you an exact conversion just yet.
I was wondering if I can get a clarification on "... adding up Paragon experience across all your heroes of specific type". Is there a limitation on the number of heroes of a specific type? For example, would there be a penalty of any kind if I have more than two Witch Doctors at P100 when calculating the shared Paragon 2.0 experience?
I was planning on starting a third and then a fourth Witch Doctor toward the goal of P100, but It may be prudent to wait for a clarification or start another hero class.