We ditched Suffolk crosses for Texel crosses in the early-mid nineties. That was with mostly homebred ewes lambing indoors, and the difference in maternal ability was quite staggering. If you want to stick with buying your replacements in then that would be the obvious first step.
Plenty of dopey Texels about now though too, as too many breeders have been lambing them under heat lamps, tubing every lamb born, etc, all of which keeps the lazy ones in the gene pool.
Moving to a maternal breed (bred from those Texels) when we changed to outdoor lambing was a revelation again.
not to mention thinking a c section is natural birth