Last I heard it was all about plate area exposed to the electrolyte, so more thinner plates for the same weight gets you more area, which is good for high discharge rates, less voltage drop.
Then they say the plates get pitted, which makes more surface area unless the pits get clogged up with sulfate. I don't know if fatter plates can take deeper pitting. PT is in charge of all that, since Mex is on holidays.
Fatter plates are also supposed to be good against vibration and shock damage. (Don't drop the battery on your foot if the battery has thin plates.)
My 12v T-1275s are 82 lbs and are rated at 150AH so 13.7 lbs per cell) they are made for running floor scrubbers and are also used in some golf cars. (4 =48v--alternative is 6-8v batts)