Speaking as someone who has used Ace VX and MV, the latter version of RPGmaker is much easier to use and infinitely better when it comes to scripting multiple events. Honestly, the two versions can't compare and MV is vastly superior when making games. Plus MV offers greater resolutions and options beyond what Ace has so it is understandable that Techno would want to abandon the headache that is Ace and use a smoother program like MV. Not to mention that 90% of the RPGmaker based games on Dlsite run on the MV engine and there's a solid reason why Techno has used MV for his last handful of minigames.
Sucks that production will stall during the transition, but so much more will potenitally be possible with MV. So many more route branches will be possible and Techno has made mention of possibly creating a route where instead of the protag and the priestess rescuing Yarizo, Leon and Iris do instead which would lead to Yarizo joining their party. And that's only one option.
Swapping to MV will be better in the long run and could potentially lead to updates coming faster than they did before, or at least maybe more content per update. With MV making the programing side easier, that would give more time for Techno to focus on the art.
That's just my two cents anyway.