To add my two-penneth worth, I have to say the quality of the plastic sculpts is overall very impressive. All the models i have seen, bar a couple of exceptions, have had plenty of character. Admittedly, they can be a bit of a pain in the arse to assemble (yes, im looking at you Torakage!), and require a little bit of filling to sort them out, but the possibilities that plastic sculpts offer over metal ones is quite astonishing.
I have to agree that certain models should be available out of the starter boxes, well, in general all of the current "minion" models (torakage, rail workers, ashigaru and wastrels) should be available as there own box sets, and i hope that when the new boxes come out I will not have to buy multiple starters just for the sake of minions.
Adding additional pieces to the plastics would be a cool idea, so not every crew contains wastrel that looks like their opponents wastrels (for example); I'm not saying we need GW-esque plastics with 100 bits that will end up in a bits-box, just some variety; a selection of alternate heads/weapons/arms perhaps.
As for crew that need X times Witchling Stalkers or X times Malifaux Rats, surely we cannot judge this until Malifaux v2 is released for public beta and we can make judgements on what is viable.
Just my thoughts.