I don't think anybody say anything about touch screen being a requirement. But basically with Apple silicon, even base Macs will have much better GPU than the current base intel integrated graphics.I'm not a gamer -but plenty of ppl that are. Small touchscreen games are complete different concepts to "full" computer games.
Even Nintendo could not figure out how to make games that were compelling on both consoles and phones.
Is an A12 Mac going to have the GPU power of a dedicated nVidia / AMD card?
There won't be an A12 Mac other than the mac mini DTK.
Looking ahead, imo there will be a renewal of gaming interest on Macs.