Despite having once really liked her, I don't think much of Aesandre now. She doesn't really get much of a look in, to be fair, which I guess is unsurprising as the production crew wanted to really identify the Opposition with Lord Fear. It's a pity she didn't get a bit more development, since she really looks the part. Her one encounter really is a let down. I'm still a little perplexed by it, since she's an ice sorceress and yet she's so easily defeated by the FREEZE spell. When she advises the team to "fight fire with fire" surely it's at least plausible to expect that an ice sorceress like her will thus be best defeated using heat, i.e. the FIRE spell. Um, anyway, that's always been a little confusing to me, and if I was writing more conspiracy theories today, I might suggest the team would have been credited with "defeating" her whichever spell they cast.
As I understand it, I think it's played that Aesandre expects the Dungeoneers to think "Ice Queen, therefore of Ice, therefore Fire magic effective!" and so somehow 'reverses' the effects so Fire won't hurt her, but Ice will. She tries to out-think the team, but in the end the team out-think the out-thinking.