I think so...but not all of them are "necessary"....like changing over to the Type 2 bolt/carrier design.
The enhanced trigger is worth it as are the newest models of BHO and ambi mag release. The ambi safety is meh....I like mine, but I mod them all by making the right side lever very thin so it doesn't get in the way of my firing hand.
I am a big fan of the Keymod uppers b/c they are so slim and lighter weight.....but the cost is very high to change that over. And competition length is my preference for 16" or longer bbls and it's even more expensive still.
I much prefer the FAST stocks to the old tube folder in terms of adjustability.
Gas systems....the Type 3 does seem to offer the most settings and is well thought out (you can't launch the dial down range).
I prefer light bbls in all the calibers.....and now most of them are actually available.
I honestly haven't noticed any need for the newest extractor spring design, or the omni deflectors....though I bought a bunch and have just failed to install them on all my XCRs.
Things are VERY slow here these days. Glad to have you back though.