I must admit I very much noticed her absence. She had her own arc in Betrayal, and was central to Luke and Ben's conflict in LotF. But would I say she was 'fridged'? Not really. DNT was very much about her and Gorog and the potential that she'd killed Padme. We also had her personally decking Nom Anor and she was a fully rounded cast member post-illness. Just because she wasn't a PoV character as often doesn't reduce her relevance.
I think Mara overall was very well utilized after the Thrawn Trilogy by the rest of the EU, in fact, i think Zahn himself became one of the few that mishandled her compared to other authors' more balanced view on the character.
I think she was pushed to the back of the first part of NJO, but she came back in a big way. And she is good support player/lancer to Luke in the early LotF books. But I do think Zahn did not do good things with her, starting with how he ended her arc in TTT.
For me it works because that she found a loophole to deactivate the conditioning doesn't mean she wasn't doing it in order to defy it or that she didin't make up her mind on sparing Luke beforehand, to me if she didin't have Luuke she would have still gone forward with their life as an ally of the heroes of yavin, with Palpatine's last command bothering her, but never following it, maybe after proper Jedi training and meditation she could erase it, or perhaps it would go away with Palpatine's final death. Point is, i think Mara wasn't a slave to Palpatine anymore way before she deactivated the conditioning, and i think it was clever to "fulfill" it making Palpatine's power seem omnipresent and impossible to simply erase by willpower, it makes Palpatine look more powerful which is good. But yeah i can see why it would seem weird for some people.
I just found it weak. And I didn't like that she never had a rejection of his evil, she just 'tricked' his command (and even that doesn't really make sense, since his name wasn't Luke it was Luuke). if others find it smart that is fine, but I just didn't think it was enough. I think it needed her to REJECT being Palpatines servant. Not someone who seems only to not serve him because of circumstance she had no control over.
