Generally speaking, most plugins have been ported to ST3, with one or two exceptions which typically were dead projects at that time anyway. I guess what matters to you is that plugins that you find useful have been upgraded. Chances are they have been, but without any idea of what they are you're not likely to get a more useful answer.
As to the gist of your question. ST2 vs ST3... If you're completely happy with ST2 stick with it. Guessing you weren't as you switched away. If there is a single feature in ST3 that's useful to you, upgrade unless there's a compelling reason not to. In my experience, ST3 is like having some upgrades to the engine of a cherished car. It's not a different car, but it feels a heck of a lot nicer.
Personally, trying to do real work in Atom was a chore simply because while in broad brush Atom copies Sublime's UX sugar, it misses a lot of the details and although improving it's still lacks by a country mile. Twas also too damn slow.
The only thing that's tempted me to switch a few times is phpStorm, simply because it has a lot of code intel features which can be quite a timesaver. But in the end it's not enough to tempt me away and there are too many little things about phpStorm I don't like; it reminds me too much of the various IDE's that I used to wrestle with in the days when I always ended up back in the comfort of my favourite old editor back then, Brief.
If I could have the the code intel and formatting features of phpstorm in an open and extensible framework, a whole raft of little bugs fixed and a bigger API to allow more of Sublime to be customised, I think Sublime would just about be my dream editor. As it is, it's not so far away. Oh, that and an engine that handles very large files more gracefully. And, and and...