Tribal - or creature types matter - has consistently been one of the most popular mechanical themes in Magic throughout the game's history. Ever since Alpha, players have loved "lord" creatures that pump a particular creature type and grant bonuses besides power and toughness, and Onslaught proved that tribal themes could sell a whole block. Even though R&D likely has reservations about large scale tribal mechanics in the future, thanks to concerns over linearity and the lessons learned from the reception of Lorwyn, it would be impossible to write off effects that care about creature types from any future block, even if it's just on a couple of cards at a time.
Mark Rosewater knows about both the demand and the design difficulties involved here, and he answered a question about "combative" class creature types on his blog in a way that might indicate the future.
When dragonoffreedom asked, "Of the creature types Warrior, Soldier, Knight, Berserker, and Barbarian, which would you like to see more of and which are we likely to see more of?" Rosewater responded:
I think we’ll see more of all of these over time. The one I’m most interested in seeing more love for is Warrior. (I’d say Soldier but Soldier has gotten a lot of love over the years.)
For one thing, he included the Barbarian type in the list of things we'll see more of - the creature type's been all but retired since Coldsnap, or, in other words, hasn't seen new creatures printed in about eight years - and, suspiciously enough, Barbarians seem to perfectly fit the flavor of Tarkir block. Secondly, even though he wasn't asked about creature-types-matter effects, but merely the types themselves appearing on typelines, he specifically mentioned "more love" for Warriors, rather than just "more" Warriors. Now, Warriors are not an unusual creature type by any means - black, red, and green tend to get many of them every block, red and green most of all - but they have only gotten actual tribal support in Morningtide. Perhaps Tarkir has more in store.