Here is the tweet:
VITA の後継機が欲しいなあ。Switch が出たから少し気持ちは落ち着いてるけど、もうちょっと小型の次世代携帯ゲーム機が触りたい。物理キーの無いスマートフォンでは満たされない欲望を満たしたい。— yokotaro (@yokotaro) March 18, 2017
And here is the translation from Siliconera:
“I want to see a Vita successor. That feeling has calmed down a bit after the release of Switch, but I want to play something on a slightly smaller next-gen handheld console. I want something that could satisfy my itch that can’t be done through a smartphone without physical buttons.”
I would be interested in what a PS Vita 2 would look like, but I have a hard time believing Sony will ever make one.