i think for a different size, it makes much sense to just pick a different species.

but there are other interesting aspects people could breed for. like selecting for a nice docile character or for a good feeding response or for health and longevity or for large clutch sizes and good fertility. if people factor these things into their decisions to a degree, BPs may be even better pets in a few decades, like in 30 years or 50 years.

i suspect if its not about color/optics and morph combinations, what people mostly select for is good feeding response and fertility and large healthy clutches.