Personally, I have no qualms either way. VOCALOID started out just as obscure at one point, so I'm not going to hold that against CeVIO & 1st Place for wanting to try something out here... the thought of potentially up & coming software makers not get some footing somewhere is kind of disappointing, as someone who likes to see some trial and error where there's actually room for it. I've been seeing a lot of that hinted in responses around the web to the news as of late just because once one thing is established, it needs to stay that way forever and always, to be quite honest.
I can SURELY understand the disappointment, though. I also still have a yearning for it to be a V4 English bank, since that's something I'm accustomed to using already, as well as many others who came up using IA since her intro in V3. Plus VOCALOID editor just provides a little more customization with phonemes at current in comparison. It's just way more convenient to be able to use her vocals in that format, and it would be more consistent to how the vocal samples would be rendered. That's the main part people lament, and I am right there with y'all. The reason why I'm even still hanging with VOCALOID is because I fell in love with how easy & pleasant sounding IA's vocals can be as a VOCALOID, and that won't change any time soon. (In fact, I still lament the fact that I can't really achieve the same clarity in her talk voice as I've heard in her concert monologues, even just playing around with some things... CeVIO just doesn't have that flexibility as of yet.)
But, as I mentioned on Twitter... 1st Place has laid it plain every time they introduce IA to new audiences: they see her more of a virtual artist before strictly being a VOCALOID. Which is probably why, if indeed confirmed a CeVIO bank, they're trying this out. They have the room to do so now, it's year six and at the very least, it can't be denied IA has at least gathered a decent little following in the years they've been working on her, both in character and voice. They're at least banking on some of us to give it a chance, as well as reach out to newer folks looking for additional options outside of just VOCALOID, UTAU, etc. (Because when you think about it, there aren't very many viable alternatives, especially for English speakers...)
I'm still not too big of a fan of the way CeVIO renders its samples, though, I'm fighting with that constantly in my personal sound experiments, even with how natural sounding the flow of the phonemes are... sometimes I feel like I end up accidentally over processing the vocals when I'm mastering the audio with the amount of VSTs & plugins I fiddle around with for clarity. Despite all that, I'm hoping as time goes on, those sound issues improve along with interface changes and additions for extended usability.
The only way that's going to happen is if they do at least get the opportunity to open up to a wider audience & market to get more input from, and this is surely one way they saw to do it I guess...
Either way, I'm just hoping for the best.