There cannot possibly be less to do about colonization in the new system than in the current system, so I don't see why that would worry you.
I'm not talking about the specific mechanic of sending a colonist, which in any case remains.
I'm referring to the opportunities and choices he has with the resulting provinces. What buildings to build and where, weighing up monarch and gold costs and opportunity costs versus longer term income benefits. Where to put colonies such as to get the right borders (admittedly applies much less in Americas than elsewhere).
In the new system, you lose all direct control over buildings, and you never have any of your own borders.
It doesn't appear that you gain all that much in terms of interaction. A single button to raise tariffs, and then wars now and then as it gets high.
On the other hand, you will still have trading decisions and those calculations will probably be more complex because you're now weighing up income you make from the trade power you get from colonials versus the direct tariff income, thus eg collecting or steering might be more of an interesting decision.
It's true that the Americas never represented a huge variety of things to do. Though with the new tribal natios, but without colonials, they would have had more. And if, as I anticipate, colonials extend (in some form) eventually to Asia and Africa, it will be a bigger issue those places, I'd think.
But you certainly do lose some control and decisions, primarily related to buildings, so the question is whether having a new type of permanent subject, and the tariff / liberty desire mechanic, will provide an equivalent, or hopefully greater, range of tasks and choices and strategic considerations. Because the concern is that you just end up watching the AI and occasionally increasing tariff % until you fight a (probably easy) war. I hope unfounded!