While I prefer Akali's VGU to be some time soon, Riot do what it wants and I respect that. VGUs only happen when they found a solid direction for the champion, hence a VGU will be ready when it's ready. There's no point trying to do a VGU for the sake of it and not do it properly, as they have learnt several times in the past.
The assassin update changes to Akali was only a placeholder until her VGU comes.
https://boards.na.leagueoflegends.com/en/c/developer-corner/QjJgio3P-assassin-roster-update-katarina?comment=000d0000
We looked into Akali pretty early on in the Assassin update and concluded that she probably needs a full VGU to get her to where she needs to be. We didn't want to push out a update that only fixed some of her problems as that hasn't netted great results in the past.
https://boards.na.leagueoflegends.com/en/c/developer-corner/QjJgio3P-assassin-roster-update-katarina?comment=0069000000000000
As for going back to older reworks. We already went back to Cass for the mage update. When we get to the Tank Class update we will likely give Shen a little love. Morde and Skarner are now on our list to get full VGUs one day (We skipped Akali because we didn't want a similar situation to Morde & Skarner, for example)
So while several champions deserve VGUs, including Akali, they will be ready when Riot has found a solid direction first.
As for mentions of Akali needing a VGU (2015):
https://boards.na.leagueoflegends.com/en/c/gameplay-balance/cNYALVBp-riot-is-it-acceptable-that-akali-functionally-only-has-3-skills?comment=0006