The 16:9 is really meant to be for those who play on mobile, which by now, as far as I recall, seem to be the majority of "official players" who download the game from DC's sources. Else it's certainly true that everybody will benefit from the additional space for interactions, the bigger map, a possible new UI, etc.
Given that, as far as I know, the background stuff kinda was his old job before he started working on SS, he probably enjoys them quite a bit and doesn't want to compromise. Then again, they are a significant upside compared to many, many other games who don't care about such things/details at all. I'm pretty sure that the game would just be "less good" if he'd rush his backgrounds like so many others do.
While the lack of scenes is a major downside, it's not like that's anything new. The game has always been "weak" on the NSFW stuff compared to many others and one could even argue that the tech update actually helped here, given that we got/will get ~18 scenes which we likely wouldn't haven gotten (now or at all) without it. I'd like to have more scenes, too, but it's not like I'm surprised that there are comparatively few...
Edit:
It's not like I agree with the all of what DC does and I really could have done without the tech update, but I can see why he wanted to do it. It'll almost certainly be benficial for the game in the future, even though it's a huge pain now.
To me the main problem is actually, that their planning has been really bad this time and that they didn't hire more posers before they started. The actual backgrounds for the tech update are done since ~september and it certainly should have been realease comfortably last year, if they hadn't messed that up.
While he's working on Ronda's stuff, I'd guess it's still far from being done. I haven't followed that many streams in the last weeks/months, though.