in the video with the Oklahoma biologist they talk a little about stunting at around 40 minutes. in stunting he says there will be a lot of small crappie, but also they will almost all be around the same size. is that what you are talking about ?
which lakes do you think this is happening ?
are you suggesting that increasing minimum length limits or reduced limits would solve this ??
this a little bit older article, but a nice review on some real world data on the effect of length limit on crappie
Crappie Science
I have talked with other biologist who refer to crappie populations as notoriously known for "boom and bust years" , which happen for all kinds of reasons.
a quick look at the agfc fishery scientific reports for lake Conway and nimrod, the 10 inch limit for Conway implemented in 2015 has been good, but the crappie stocking program didn't make any significant difference.
for nimrod a 10-inch MLL was implemented for the harvest of crappie in 1994. This MLL was rescinded in 1999, when data suggested that growth rates had slowed down significantly
Fisheries Scientific Reports