Thanks for the advice so far!
what did YOU like in 5e?
There is your answer 
The sad thing is, I don't have a LOT of experience with 5th. Read/Own some of the books, but barely played it. Most of time spent playing/running was under 4th. Now I think 4th is fairly solid, for the most part. Some of it a little complex.
I was considering pulling in:
Initiative Passes (need to re-read, just to make sure it's viable)
Single Armor attribute - Just one number for everything, for ease.
Decks (I'm a traditionalist - though I plan on actually following the flow of the events/world, starting at the beginning of the 4th era, then working it through)
Things I'm not sure on:
Modifying the melee damage to STR+ instead of STR/2+ - how does this impact combat overall? Does it require a reworking of guns to keep up?
Limits - in a way, I like them. In a way, some of them feel REAL arbitrary. I don't want to get into the pros/cons arguments, but it's a mixed bag. If I can't make myself REALLY get behind it, I don't think I can sell it to my players. The whole