Against V5:
Yamaha might be moving away from V4, or they might be moving away from Vocaloid. Scary though that sounds, they've been pretty quiet lately. Voctro Labs, made up of Vocaloid's original developers, appear to be pursuing an independent route with their own synth. 1st Place has transitioned to CeVIO, why? Did CeVIO make them a generous offer, or were they avoiding abandonware? Crypton has shown interest in SynthV; how strange of Wat to promote a competitor. The original father of Vocaloid left Yamaha around the end of V3, will Vocaloid still be of interest to the company without it's original proponent?
For V5:
V5 is overdue, and the usual engine life cycle has passed. Although cutting ties with lower selling Vocaloids makes sense, it would be a surprise for Yamaha to stop directly selling their flagship, VY1. Cyber Songman hasn't been out for long, so to lose him would be sudden too. It may be a sign that the V4 editor is central to the majority of cuts, suggesting they are making way for a replacement.
Vocaloid buzz in Japan has calmed down, but it's still a steady presence that's broken out big time in China. Major third party developers like Crypton and AHS remain as active on the scene as ever. Not so long ago Yamaha reached out to the English speaking community for the first time to promote the software with tutorials using Diva and Songman. A last ditch attempt to make sales, or the beginning of bigger plans?
tl;dr I'm curious for what will happen after the 12th.

Oh PowerFX, if only you were with us now.