What did WE learn in OEF/OIF, that is going to help the next generation win against ISIS?

More than can be expressed here. Hearts and Minds! If we go back in, we have to stay for the long hall. Can’t just cut and run when the administration changes. Somebody other than the US needs to be footing the bill. If we are going to be your country building police force, then pay the cost.

We learned quite a bit. That's the good news. The bad news is those people who learned those lessons are being forced out and the Army's letting all that institutional knowledge walk out the door.

Don't retreat when winning

Wrong question. People need to understand that ISIS is a direct result of our involvement in Iraq. ISIS is what happens when you oust a numerically inferior/militarily superior authoritative entity (Saddam Hussein/Ba'ath Party) by force of arms, hand over a power vacuum to a numerically superior entity that draws religious and political authority from another country (Shi'a), then completely disenfranchise the former from any involvement in the future political processes. Oh, and topple Qaddafi and ship his armaments to the FSA, where all those disenfranchised Sunnis ended up.

The question you *should* be asking is, "What can we learn in the way of shaping US and western foreign policy in order to avoid such blunders in the future?" To which the answer is to stop electing the same old members of longstanding political dynasties who have more in common with each other than they do with you. And to demand an end to unjustified war predicated on nonexistent reasoning.

Have a full, detailed Phase IV plan developed and ready to implement as soon as the majority of the fighting is over. "Make it up as you go" is not a Phase IV plan.

We have learned what our Vietnam brothers learned; the government doesn't have our backs or what's best for our respective services, again. Why do we have to relive the administration repeating the same pull-out of a combat zone before we are done, leaving a vacuum in our wake, AGAIN?!

Don't leave behind any equipment that can be repurposed by our enemies to create terror weapons. Up armored Humvees filled with explosives, used as VBIED's are extremely hard to stop. We didn't leave any useable equipment in the Chosin Reservoir...but we did in Iraq. Terrible waste of assets the enemy quickly employed to their advantage.

Probably not a topic we should discuss on an open source forum... Just my 2 cents

Can we begin with the premise that the only thing we get right 100% of the time is incorrectly predicting and preparing for the next war? We were prepared for HIT, and we got very little of that. We got CI. AWG is one of the best lessons from that conflict and the use of CA.
Personally, I believe we are losing against ISIS. We have failed to adapt. The war is being fought in real time and broadcast on the web and in the media. I believe our Cyber Warfare capability is immature (compared to other nation-states and non-state entities) and fractured. You can kill 10s of thousands with a cyber attack and create mass chaos with a dozen soldiers with the right skills by hacking infrastructure such as power grids, traffic signals and EMS communications. Divisions of troops cannot combat those threats; we do not own those Soldiers. I believe that a few dozen homegrown lone wolves (or coordinated cells) will bring the attack home. Further, we have failed to capitalize and manipulate our enemy's enemy into attacking ISIS (Syria) for fear of the political (in)correctness implications.

What did we learn? Probably nothing. What should we have learned? You can't win a war when the Geneva Conventions are tied around your balls.

Or strategy for dealing with ISIS? Let them take over that whole region with their "convert or die" attitude. Then we can safely assume that everyone there is a member of ISIS so we don't have to feel bad about leveling the entire region.