Well, first and foremost - played some good games last night. Intense would be the right word. We just happened to play against some serious competitors.
Here's a couple things that seem to be really the norm these days on Isis (and probably on other maps too, but these are just what I was looking at).
Putting Engineers on Patrol
Isis is a strong map for patrolling engineers because they'll suck up a lot of metal off the walls. This trick has kinda come out of nowhere, but it seems like it works. If you can put down 4-5 engineers, every time they zap they'll suck up a little 50 metal bump. Doesn't sound like much, but when you've got a bunch of them working on it, that's literally thousands of mass resources that you otherwise wouldn't have.
Achieving Air Superiority
This seems to be pretty true for games where you try to turtle in the base - if your opponent can get a lot of air units up, they can distract your fighters and just cause a lot of problems. Even when you're getting in to T3 anti-air, there's still a lot to distract.
Support Commanders as Combat Units
A lot of people now seem to be really comfortable using support commanders, with their 20,000 health points, as combat units. Personally I find myself using them much more as resource builders. But again, Cybran is a freakin strong faction on this map. They apparently have an upgrade called "self repair" which is just insane. I sent 15 T3 siege bots against a few support commanders in the hope to take a couple of them out. Instead - my guys were busy shooting and when I'd look at their support commanders' health - they were full! It was absurd actually.
Cybran really does dominate
Sorry, I hate to keep saying this, but on this map, Cybran's experimentals just really define the gameplay. Spiderbots can be used both on offense and defense, and the Soul Ripper is just SO much stronger than it used to be... It's pretty difficult to hole up and maintain any kind of air superiority. And of course, the Scathis just requires that you shield-up almost your entire base, which can be costly and time consuming.
So, anyways, that's the latest strategies from the land of Isis.