It does seem like a lot of hogs, but with that much rain and supplemental feed it must be doable in that situation. I am considering a set up similar to that on my place, though scaled down a bit. Also I do not plan on a stocking density of that number. I do not receive that much moisture here.
That is a LOT of pigs! I can't imagine there's much left for them to graze after the first few days!
We provide our pigs with containers of water in addition to their swimming pool-wallows (that they usually dump to make mud wallows). So for much of the day they have clean water and the mud they love.
The rooting, even of smaller pigs, makes all kinds of ruts in the field. It's really hard to mow after they're done rooting there. One problem I see with his system is that after a year of this, there would be some pig-resistant weeds left that would be best mowed to keep them from spreading, but the pigs would make mowing with a smaller tractor more difficult. Keeping sheep in the pastures and putting them on a few weeks after the pigs have been through might help with that problem. Specifically sheep because they like to eat forbs, which are the broad-leaved weeds, but they'll shear the grass down too. For some reason my pigs are selective eaters and even after they've been in a paddock for too long there will be long tufts of grass they, for whatever reason, don't want to eat.
I'd make the paddocks smaller and rotate them through a little more often. It only takes about 2 months for seeded pastures to fill in again. I seed my bare areas with whatever will be the most useful for the next time they're allowed in there - clover, annual rye, corn, etc. Assuming no regrowth happens in the hottest part of summer or the dead of winter, they could still be each paddock 4 times, I think. I'd rotate them quickly through in high summer and the dead of winter just to graze off what's there then shut them in the "hub" with feed until they recover when the weather improves again.
One more improvement would be to plant (protected) trees for shade and fruit/nuts - i.e. a silvopasture. Apples, mulberries, oaks, chestnuts, peaches, wild plums, etc. can provide even more free food. I'd start them from seeds and grow them in a nursery bed for 2 years then transplant them out, surrounding them with strong fencing until they're strong enough. An easy way to do that is to plant them along the dividing fences or outside the perimeter fence (tho then you'd lose the half of the fruit that falls where they can't get it). The pigs would benefit from the shade, which would also encourage them to graze for more of the day when it's hot out and provide some protection from wind on chilly days.
We do about 10 pigs per acre sustainably with little supplemental feed and no commercial hog feed / commercial grain. Most of our pigs's diet is pasture which is supplemented with about 7% of dairy most of which is whey. We have about 400 pigs on pasture with about sixty breeders and have been doing this for a little over a decade. Change the variables such as more supplementary feed and the number of supportable pigs will change per acre. I find that the keys are managed rotational grazing, good pasture development and good genetics.