Victoria 3 based on Imperator: Rome v2.0 - Interesting?

[Ketchup & friends]

Yes, they ARE.

Many key problems (lack of diversity, No immersion, too short etc) are still there.
And new mechanics lack polish.
Besides you're ignoring the patches between 1.0 and 2.0. It was gradual improvement, not one jump.

Imperator still has many problems, but it is now much closer to Vic than to EU4.

Yes, and becoming more like Vic2 is a good thing.
But it's still not good enough.

If PDX need a game as prototype for Vic3, they should use Vic2, not anything else.