1. Scrolling up or down toggles off the auto sidescroll (with the stop bar, when the song is playing). This seems small but ends up ticking me off to no end. V4 doesn't do that, nor does V1.
2. You can't scroll side to side with the two-finger swipe on a touch pad. I'm probably in the minority of using V5 on a laptop(?) but it's just really frustrating that V4 lets you and V5 doesn't. (V1 doesn't either but I give that a pass for being 16 years old)
3. Rendering. Why isn't there a "play with render" mode? Unless I'm super blind and just missing it, but I haven't been able to find anything. Like someone PLEASE tell me if I'm missing it somewhere. If not? Puzzling how it's taken a step back from all 4 generations ahead of it, in this regard.
4. How long it takes to open. I guess there's something to be said about running it on a more powerful machine than my laptop, but it IS a gaming laptop that I bought specifically because its specs are able to handle programs like Solidworks and MATLab etc for university. V1/2/4 open fine, but V5 takes ages. By the time it does finally open, half the time it crashes if you select a VPR, and you have to wait again anyways.
5. Vibratos are hidden under release effects. I'm sure most people use the attack/release effects for most of their tuning in V5, but it's just a little weird to me. Doesn't really come to mind as something I'd categorize as a "release effect", you know? Probably, it's more intuitive to someone who didn't get used to V4 and back first, but for a while I was just right clicking the note, totally puzzled as to where the vibrato menu would be. Plus then instead of being able to go into a vibrato menu and edit its shape etc, you have to use the emotion tool to open a menu and drag it around a bit. Just very... inaccurate and frustrating.
6. Exciter is really cool, but it does add some pretty audible engine noise to a voice. I'm sure it could be improved upon, should Yamaha ever pick Vocaloid back up again.
7. Some parameters' names were changed needlessly and sound similar to new ones. Like now we have "Breath" and "Air". And "OPE[nness]" (which I think made some sense) is "Mouth" which... arguably is less illustrative about what you mean that parameter does.
8. In fact, why are the parameters hidden upon a fresh install? In that teeny "+" button in the bottom corner. Super easy to miss. At first I was genuinely confused and wondered if I'd somehow missed that they'd been removed.
9. Can't move certain attack effects around. For example, vocal fry often sounds like it's a little too early, and this especially mixes oddly if there are notes very close to the one you're adding to, but it insists it's at the perfect position and you can't move it any. Which seems strange to me, since vocal fry is essentially just fancy PIT that you can imitate in older editors with a little work. Makes me just not add it to a number of notes that tbh it would sound good on.
10. You have to edit phonemes within the attack/release menu that displays phonemes? At least, that's what it looks like. I was told a little while back that if you do Ctrl+R to get to phoneme mode, then you can click on the word and it'll let you edit the phonemes directly on the note, but it's strange that it doesn't do what V4 does where it displays the phonemes directly. Who would think it'll let you edit phonemes if it's still showing the regular words? I say we go back to the glory days of V1 where the word and phonemes were displayed separately, both on the note and edit-able at a click
11. Can only have one attack and release effect per note. Maybe I want a vibrato AND a decrescendo. Nope, back to manually editing parameters for you!
12. And of course, as your local V2 apologist (bank-wise, at least), that V2s aren't able to be imported. I've heard the reasoning that they're lower-quality, or that their lack of triphones is to blame, but TBH I don't... really care. Like I get it. But it doesn't make it up to me, when they work in V4 and V5 is so similar to V4 that early fileswappers were able to get V5 voicebanks to work IN V4. And there are a number of V2s that are honestly still good voicebanks. To this day I think Miku V2 holds up as a genuinely good bank. Yamaha's reasoning is their own, and it's their decision -- but I don't have to like it.