None of the issues you mentioned are really fixable. Online streaming is a bit of a pipe dream for linux, legal(ish?) solutions are going to be hacky and break constantly since nobody has the negotiating power to work out deals with labels. Same with videos, alphabet is not going to just allow random apps to bypass the entire point of youtube (serving ads to eyeballs and tracking said eyeballs to serve more ads). Maps does suck, and that's mostly and openstreetmap issue. You could integrate google maps but those API keys are not cheap.
The Videos app likewise plays your videos. No idea where you're getting that bit about The Guardian, but that's just flat out false.
There is no first-party Maps app, so again, that's not something that the elementary team provides...
Constructive criticism is helpful, but only when it's informed.
I feel like the more internal team relies on them, the better they are. And, well, I guess they don't use multimedia apps a lot.
For example, the Music app. Comes built-in, looks great, only works with your local music library if you copy it over and reorganize it the way the Music app wants. No online music streaming of any kind.
The Videos app? Again, only your local library, and that's it except (IIRC) it has videos from The Guardian newspaper of all places as one of its four online sources? What's up with that?
The Maps app? Looks beautiful, again, but the last time I tried it, it could hardly handle directions. Maybe Directions work well now, but it's just... not good.
Every app is like this - barely functional.