There's merit in a role-based approach like this. However I don't agree with the whole "in order to tame a Utahraptor, you need to first tame a Microraptor etc". The way I could see there being merit in taming "lesser" dinos within their size/role is you gain a passive buff to taming the "next dino up" - so if you go straight for taming Utahraptor, you have a 0% bonus to taming Small Dinos. However if you've tamed Microraptors, Velociraptors and Deinonychus before attempting a Utahraptor tame, you have a 60% bonus (the number is arbitrary, as an example only) to taming Small Dinos.
Your examples are all carnivores though, so how would this approach affect herbivores? And what roles would they serve? The same, or herbivore-unique/specific?
This. Once you get a Raptor, Dilos become obsolete. Once you get a Carno, Raptors become obsolete. Once you get Rexes, Carnos are obsolete and the only thing you fear are other Rexes, Gigas and soon Carcharadontosaurus. You end up culling dinos because they serve no purpose anymore.
There needs to be a reason to keep your "lesser tames" around. Like "milking" your Dilo for poison which can be made into a powerful tranquiliser/narcotic, as an example. And, so you don't need to have bases full of dinos, whatever their (secondary) use - you don't need *that* many of them for it, or perhaps (like a Gacha in ARK) the more of them in an area, the less effective they are at this (secondary) use.