The update was likely meant to be a ~3,5 months update instead of the ~5 months it almost took at the end. We got 0.19.0 at the end of october while 0.19.5. dropped mid december and was really fine for an ~7 week update. That means they then really started working on 0.20.0 after a chrisitmas break in late december/early january. After that I'm sure that DC getting his third child and being sick for a week, while having his older child at home all the time, Sploosh having some troubles with the dialogs, etc. caused some actual delays. Almost the same stuff that happened during Diane's 0.17.0 update. I'm not quite happy that they didn't communicate this a little more clearly and that we have to read between the lines, but at least I've got some hope that 0.20.5 won't last another 5 months.
The update itself was fine to me, though I'd agree that Tina is kind of an extra storywise for now. I'd really hope she'll get an actual role in 0.20.5. or else she's really just Ivy 2 and could have simply replaced her in one way or the other. On the other hand it's nice that we've got Becca's mum, which means we may even see Missy's sister, etc. too at some point. Alone for the dialogs I'd want to see her.