Every Handheld has had the Capability to play games from every single region out at the time of the Handhelds lifespan:
GB: Kanto
GBC: Kanto through GB backwards compatibility, Johto
GBA: Kanto remakes, Johto though GBC backwards compatibility, Hoenn
DS: Kanto remakes through GBA backwards compatibility, Johto remakes, Hoenn through GBA backwards compatibility, Sinnoh, Unova
will the 3DS continue that pattern or not? Currently, it has Johto BC, Hoenn Remakes (though unreleased), Sinnoh BC, Unova BC, and Kalos so all it needs is Kanto to be finished for its time period.
So this begs the question: will the pattern be broken or will there be a VC release of the Remakes or a VC release of the originals or a Kanto Remake Remake. Anyone's guess.
GB: Kanto
GBC: Kanto through GB backwards compatibility, Johto
GBA: Kanto remakes, Johto though GBC backwards compatibility, Hoenn
DS: Kanto remakes through GBA backwards compatibility, Johto remakes, Hoenn through GBA backwards compatibility, Sinnoh, Unova
will the 3DS continue that pattern or not? Currently, it has Johto BC, Hoenn Remakes (though unreleased), Sinnoh BC, Unova BC, and Kalos so all it needs is Kanto to be finished for its time period.
So this begs the question: will the pattern be broken or will there be a VC release of the Remakes or a VC release of the originals or a Kanto Remake Remake. Anyone's guess.