The spire control point can be a difficult one to capture if the enemy has their defence together. The defenders’ advantage lies almost entirely in the battlements; they can use them to sniper the long path down the hill, shoot out the little concrete hole to harass those coming through the house, and most importantly fire on enemies capturing the point from the left of the battlements. They can do all of this while being reasonably safe from enemy fire – they defend on their terms. To shake things up for them, a soldier or heavy combined with a medic can enter the base through one of the lower entrances (not used much since they all head to the battlements) and head towards the battlements themselves. The defenders will be unprepared and you can clear out the battlements, allowing your team to get the foothold.
The middle control point has a lot of strategic elements to it. Apart from the plane containing the control point, there’s a height advantage to be gained from standing on the flatbed carriages, cover provided from the tall stone columns, and players go mostly unnoticed if they go under the bridge. This gives forward engineers a great variety of placement options for their sentry guns. They can place them under the bridge to attack those who fall off, behind columns so they go unnoticed until an unaware enemy walks past, next to the flatbeds to cover the control point with cover from enemy rockets from the windows, the list goes on. Be inventive!
Valve said the theme of Badlands was variations in height, and those variations are very apparent if you’re looking for them. This can give a great deal of power to demomen who can better utilise the element of surprise. For example, shooting sticky bombs from beneath the middle bridge into the capture zone while avoiding enemy sight, and similarly on the spire control point, lobbing bombs up to the top either from the base using the spire itself as cover from enemies on the other side, or from the battlements, shooting over the metal fence. Look for the angles to surprise your unaware enemy.
Defending the last control point often goes very badly. The most important thing to keep in mind is the recapture of the spire control point – without it, you are pretty much stuck inside, giving up massive chunks of map control. At the same time some (backward) defence is critical – a scout can dart into the room and capture the point in a second or two. Given the semicircular protection from the glass tube, a heavy standing on the point spinning his minigun is generally enough to fend of small insurgencies, so the defenders should place a single heavy on the point, perhaps with a medic and demoman, and push ALL of the rest of their team forward to attack the spire. In the process they’ll be killing off attackers and indirectly assisting the defence anyway.
Class mix is very important on Badlands. Sometimes it seems more important than other maps, though I might just be making that up. If I had to pick 12 players I’d go with 1 scout, 2 soldiers, 1 pyro, 1 demoman, 1 heavy, 2 engineers, 2 medics, 1 sniper, and 1 spy. If they all pretty much go about their roles standard roles, they should do very well. However the trend seems to be to have too many snipers and spies, and never enough medics. Again 2 medics should be the absolute minimum in terms of efficiency.