With the confirmation of separate Pokédexes for Alola, I felt this might be an interesting topic to discuss.
The introduction of separate Pokédexes have allowed for wider variety within a region and allowed for massively large regional Pokédexes. However, this idea also disallows encounter with later or earlier stages of a given species, as each Pokédex contains unique species which also translates to non-encounter of that species' family in different stages of the game beyond where it is encountered.
This also encourages grinding, as it is next to impossible to encounter and capture a later stage or later level version of a species in wild.
So, what do you think? Should we continue with this idea?
Or should we return to B2W2 style Pokédexes, where an individual region has a large regional Pokédex but families are repeated throughout the region, including both appearance of different stages of the same family, but also repetition of those stages in different routes?