What is the best way to take out a sectopod?
Have a heavy learn 'shredder rocket' and 'heat ammo'... Hit the sectopod with the shredder rocket, so it takes more damage from hits over the next few turns. Then have the heavy with 'heat ammo', which allows it do double the damage to robots, attack it. Furthermore, if your heavy has 'bullet storm', then he can fire at the sectopod twice.
My strategy was: Snipers. Snipers Everywhere.
Basically I had a max rank sniper with a laser sniper rifle and a mid rank sniper with the regular rifle when I first encountered the sectopod. They both have the Squad Sight perk so I basically put one guy up close enough to see it and then threw some smoke on him and had the two snipers shoot the damn thing to death. When I actually started fighting it, the sectopod was the only thing in the area (It did have the drones and two elite mutons but I retreated back so I could unload on it when it appeared, I later found out what you mean by nasty AoE)
One sniper had Double Tap (The laser one) and I basically just dropped it's health from full to about 1/4 quarter left by having my entire squad focus it while it could only shoot the guy in full cover in smoke. This may have been a one off thing though since it was on an overseer crash where there was a high vantage point for the entire area I parked my sniper at.
It seems like not many people think about this:
- Sniper with disabling shot, disable its weapon.
- Charge your assault(s) forward and blast it (with rapid fire, if possible). Only do this if there are no other enemies around
- Have support kill off any drones that may be lingering.
- Heavy do the same if any drones are left, or just hit the sectoid more.