The only reason I think the 322m experience is "total exp required" for level 100 is because that's how all Blizzard experience systems work. So I assume they didn't change it. (Meaning not 99-100, but 1-100)
Doing some math, I'm starting to lean towards that table being experience required per level. Not the cumulative experience required to get to that level. If that was the case, it's only 7.2m for the first level, then 1.44m per level up until 60. After that, it's 2.88m per level until 70, 5.04m until 80, 6.48m through 90, and 8.6m to 100. Averaging 6m exp per hour, it would only take 53.76 hours to get to 100. That's not quite the hundreds and hundreds of hours that Jay was referring to. Even if you lowball it at 4m per hour, that's only 80.64 hours to 100.
I made a spreadsheet to show a curve of experience per hour and total time needed. You can get the summarized data here and the full detail ">here.
Basically I used 4m exp per hour average for levels 1-20 and increased it by 2m per hour every 20 levels. So by level 81-100, it's 12 mil exp per hour. Who knows what the best possible experience run will end up being, but this is just to give an idea. Using this average experiencing per hour curve every 20 levels, it would take you 566 days if you played 2 hours per day to reach level 100. 3h/d would be 377 days, 4h/d is 283, etc. At best, if you could average 12mil per hour all the way through 100 from the start and played 8 hours a day, it'd take 109 days, or 871 hours. Who knows though, maybe with good +exp gear, a 5 stack, and a very efficient run, we'll get up to 25m+ exp per hour.
Looks like people have already gotten to Paragon level 2 within 2-3 hours, so 10mil+ exp per hour is very plausible. Average 13mil for 1-100 would require 804 hours, 268 days at 3 hours per day of straight up grinding exp.
The good news is that its easy to get to 200 MF and still retain high damage. Which means you'll only need Paragon 34, which is only 105 hours at 13m/h, 150 hours at 7m/h.
I love this new Paragon leveling system. It gives everybody something to work on over the next several weeks/months/years. Yes, I know the hardcore gamers will be seeing how rapidly they can level up as they max +exp on what they can and play for hours a day, day after day. Personally, I play a couple hours a day 2-3x a week, give or take what my work schedule is, so getting to 100 will literally take well over a year to accomplish. It'll feel like nice lil accomplishments getting from level to level, and getting the 3% bonus/level as well will help find some nice gear for the other characters I plan on making.
I got 4,5 levels in 3-4 hours play yesterday and I wasn't really rushsing, by just doing act 3 and even skipping some stuff. I think it's fine, but getting 5NV very fast is the key. Get the easy elites asap then clear the rest