Prior to 2.0, there were a lot of fun and interesting runs you could do playing as a small nation adjacent to a major power. One of my personal favorite runs involved taking Halikarnassos and expanding to encompass all of modern Turkey. To succeed as a single city bordering a major power, you would often have to do the following:

1. Time your own wars against the major power so they occur after their manpower has been seriously depleted by other major wars
2. Time your wars against the major power to occur during their frequent civil wars, ideally declaring on only one side of the civil war at a time
3. Time your wars to occur when the major power's armies are deployed far away from you
4. Exploit the inspire disloyalty mechanic to snag territory from your neighbor
5. Exploit the inspire disloyalty mechanic to steal away armies sent against you by the major power
6. Optimize your economy to build up lots of cash and use that cash to field an army that can punch above its weight and hire a lot of mercs in an emergency
7. Exploit the relatively low cost of technology for small nations to technologically advance relative to large nations

This made for a fun game, even if it amounted to a bit of a delicate dance. Either way, you had lots of things you could try and do.

In 2.0, however, your options for play have become vastly limited. Almost all of your options above have been neutered. Let's go down the list. Yes, you can still time your wars to wait for your major power neighbor to be weakened, but it doesn't matter as much since levies seem to recover in size very quickly between wars. You can still try to exploit civil wars, but civil wars are much less frequent and much less impactful than before. You can still use the inspire disloyalty mechanics to steal territory and steal armies, but only much later in the game since a lot of this is now gated behind technologies for some reason. You can still time your wars for when your neighbor's armies are far away, but actually if they haven't raised your region's levy, they have an instant army to deal with you exactly where and when they need it. You can still optimize your economy, but it doesn't matter that much for warfare because now there is a hard cap on the number of mercenary armies you can hire. And your technological advantage relative to major powers is now also much slimmer, since the cash scaling situation is gone as well.

I'm not saying you can't still have a successful run as a small country. But it doesn't feel like as much of a different and unique experience. I think the excessive stability of major empires (both in the sense that civil wars aren't such a big deal and in that levies recover between wars so quickly) coupled with the game placing hard limits on your ability to do things like woo generals, hire mercs, etc. has taken away a lot of fun ways to play the game from small nations.

The converse to all of this as well is that playing as a large country is a lot easier now. Civil wars are much easier to avoid. Stability doesn't matter that much. You mostly don't have to worry about your generals getting stolen away and that sort of thing, thanks to the tech gating. You don't have to worry about the small powers nipping at your heels posing a greater than expected threat via mercs. You don't need to worry about the time it takes to march your armies from one border region to another, since your levies will instantly spawn wherever you click. And since levies recover so quickly, you don't have to worry that your manpower having been depleted in a big war against some other major power will leave you without forces to cope with minors declaring on you in your post major war peace period.

Overall, 2.0 made a huge number of really good changes. I don't want to take away from that. But the large-small nation balance I think has severely swung toward large nations, and in a way that makes things less fun since it as at least partly predicated on taking interesting features and tech gating them.