"Or look for more cable pull per shift; AFAIK SRAM is better in this regard."

I think that's only a valid statement when comparing brands of pre-Dynasys MTB derailers.

The SRAM and Shimano rear derailers, up till now, are roughly the same in this regard, i.e. less cable travel than Campag.

I'm told that Shimano's now 11s gruppos will have a longer cable travel, but at that level more and more riders will opt for electric.
I think that electric shifting will allow the highest gear counts, due to the absence of cable elasticity and friction.