First, I'd like the thank the mods for creating a sub-forum just for map strategy. This is the part of the game that I love the most, strategerizing!

I just have recently gotten some time in on Badlands and my first impression is that the map is very momentum oriented. The team that first seizes control of the central point is almost always the team that wins the round. I usually play Engie and getting to the central point and throwing up a dispenser and a sentry gun ASAP is my main priority. (Which I'm not always successful doing.) I've noticed that some engineers will head to the spire out of the gate and set up a base and I think that's a mistake. It's almost like you are planning to give up that first point when you do that.
Also, it's such a large map that I feel like teleporters play a big role in keeping the pressure on the enemy, allowing respawned teammates to quickly get up to the front lines. Moving your base up as your team advances is a must although if your team is capturing points quickly then it might be difficult to keep up with them and do much building. The final point is almost impossible to defend as it doesn't have to be occupied for very long at all to cap it. That's how it goes on the pubs in 12v12 battles, at any rate. The map probably plays very differently in 7v7 or 5v5 and at my best guess, I'd say Badlands turns into a scout-fest with fewer players.
Here's a cheap way to win the game if the other team isn't prepared. Have a spy infiltrate the base and hang around the final capture point while you are attacking the spire. If the other team isn't turtling up but rather focusing on the spire then when you cap the spire the spy just waltzes onto the final capture point unmolested and it's game over. If the other team turtles a little bit then he might have to sap a sentry and backstab an engineer on the way in. If they turtle up big time then forget about it and just go with a traditional assault.
Okay, those are some random observations I have about Badlands. Obviously there needs to be more discussion on specific strategies to assault or defend each point.