Integrate with Sir Trevor

Very cool! Only problem is that such UX is very hard to achieve with the Drupal field widgets/form API.
Every field type would need support for it. The adding of items might be a good start for UX improvement though.
Any idea on that?

Isn't that kinda the same thing as some fancy extended "quick editing" UI?
I would expect that quick editing as in core D8 can be extended.
The biggest missing piece is an "add paragraph type X" selector.
Note that wysiwyg inline editing is ugly in D8 because there's a (one way) filter chain from the stored data to the output.

We also already discussed that paragraph types should have icons. But that's a missing concept in core (content, field, block, view, ...) type definition.

We also need to be careful with not messing too much with (any custom) design.

So the first thing to research is, if core quick editing can back something like this completely... or if it would be a replacement.
In any case, i would recommend to push core style quick editing forward instead of reinventing it in contrib.

You are right this is kind of like QuickEdit.
I did not try to extend QuickEdit yet, but yes, I think it can be extended. Currently it just shows the full widget for Paragraphs (full table, which looks crazy ugly in QuickEdit).

I suggest to create a separate quick edit issue then... and keep this issue here about the third party library, postponed until we know how nicely we can make quick edit.

maybe this one helps: https://github.com/kevee/sirtrevor-drupal

Nah. I like Sir Trevor because of it's interface, not because of the way it saves data (and the sirtrevor-drupal module uses the same way, everything in json).
I rather create an quickedit interface like Sir Trevor.

But if components don't live as fields (Paragraphs or whatnot) doesn't this practically guarantee no way to create view modes of this content for usage in Views, etc?

We are talking of the UX.
Sure, independent of the library we use or mimick with custom code, we will use Paragraphs.
But the mapping on a plain frontend editing UI might be far less obvious than if you do backend editing.