Mantle Thickness and Neutral Defenders
Mantle Thickness determines how quickly your units are able to capture a region. For me, this affects me at two particular points in the game: in the beginning when I send out my Engineer to go capture a region before the defenders spawn, and later-game when I am trying to snag regions before my opponents discover me.
The higher the mantle thickness, the longer it takes for your units to claim an area. If you want to be able to take regions quickly and then move along to conquer more, setting the mantle thickness to low will speed up the process! But, remember -- whatever good this does for you, it also does for your opponent.
Neutral Defenders also have their own setting now, too. Before, you only had the choice of "on" or "off", but now you can add a little bit of variety to the game by setting the defenders to light, heavy, or random. I have enjoyed the "random" setting in particular because it forces me to be prepared no matter what region I am attempting to conquer. Sometimes I'm pleasantly surprised because there isn't a single one to be found, and other times I'm actually glad I sent a small army because they have a pretty solid little force built up.
Atmosphere and Orbital Coverage
There are three words I fear when playing RTS games, and it's usually what I would hear screamed across my voice IP channel of choice when playing Starcraft with my buddies:
"DEATH FROM ABOVE!"
In the case of Ashes, it comes in two forms: orbitals and air units. As I've played, I have gotten a lot better about building up a counter to both of these things at my main base (since an embarrassing all-orbital defeat at the hands of Brad a few months back, I now always remember to build orbital nullifiers).
These two new options now allow you to adjust the atmosphere of the map to either allow or ban aircraft from being built for the duration of a game, as well as enable or disable orbitals. I know that when I play, orbitals are just one more thing in a mountain of things to remember to do, so it's nice to be able to turn them off and focus on getting better at my army management when I'm practicing during single player.
I personally tend to leave aircraft on, but that's just because I like to use them. I still get pretty salty when my opponent sends over an early bombing squad I'm not ready for, though.
Nanobot Productivity
This option is a dangerous one (for me), because it's really easy to crash your economy by increasing the rate at which everything is built. Granted, you can better control your economy by decreasing the rate, but as one who hates waiting for construction (we have two seasons here in Michigan, Winter and Road Construction), I just won’t do it.
The benefit to being able to change the rate of how quickly your nanobots work is being able to set the pace for your game. If nothing else, it has taught me something about managing my economy, since building things rapidly means running out of resources and having to listen to Haalee judge me.

Entrenchment Bonus
This one is brand new! Admittedly, I haven't played with this setting very much yet. The Entrenchment option allows you to give your units a defensive advantage when fighting in territories that belong to you. This sounds great... until you remember that your opponents get the bonus on their home turf, too.
Either way, I found that I more often that defending against my enemies is more difficult than attacking them. To that end, setting the Entrenchment Bonus to Low (90% normal damage) or High (60% normal damage) has allowed me to gain a bit of an edge when I’m being attacked by more than one opponent at the same time.
The best thing about the new map options in Escalation are that you can set the pace and tone of your game any way you like. By allowing for adjustment of more than just the levels of difficulty, Escalation is a game that veteran RTS players can really sink their teeth into.