The M-113 was a great vehicle for its time and role (battle taxi), and the design was very robust and flexible, so you could make all kinds of variants. The British came up with a somewhat similar (if a lot smaller) solution with the CVR(T) family, the Russians had the MT-LB and the Swedish CV-90 is perhaps the latest go round of that idea.
There are some roles where specialization does not hurt; if I was Generalissimo and had unlimited funds I would increase the Leopard 2 fleet of tanks in preference to the CV90-120 (and with the financial situation in Greece and Spain, that idea might be doable now!). Working in the Arctic and difficult terrain isn't feasible with conventional vehicles; something along the lines of a BV-206 or the STK Bronco would be needed if we were to start operating in large numbers in the Arctic. Even the logistical truck fleet would not be based around one type of truck (OTOH, any type of truck would have to be milspec so you actually could drive off the hardpack), but again, a family fleet of trucks with some commonality in training, logistics and support would go a long way to stretching the defense dollar.
The example of the BV-206 also shows how starting assumptions change the outcome. If we are truly committed to the Canada First policy as initially articulated by the Conservative Government, then buying tanks and CCV's should actually be a much lower priority than buying vehicles capable of operating in the arctic and various sorts of logistical and engineering vehicles optimized for DOMOPS missions. We would also be considering what sorts of platforms require minimal maintenance so Reserve units could simply pack up and drive out to meet DOMOPS missions without absorbing a lot of logistical overhead.
So there is no "perfect" platform; there is however a sensible way of looking at vehicle purchases which includes "families" for lower unit prices, common logistics and support, and ensuring that you identify all the verious pieces before you put pen to paper and end up forgetting or foregoing the various support verions of the vehicles you intend to use.