Fishing line works well. Wiring frames main function is to help keep the foundation from warping and bowing before the bees get it pulled out. It does aid in support for extracting new comb but if you run the extractor right you shouldn't blow out the frames except on rare occasions wired or not.
What RR said..
I HAD some deeps strung with 40 lb Big game line and never had any problems with them. AFAIK the new owner is still using them.
Mono line doesnt degrade badly unless it is left in the sunlight. I have six year old 40 lb big game line that I still restring my river poles with, so I cant imagine degradation being a problem before those frames need to be rotated out.
I think its a matter of preference and method mostly.. If your using them as brood frames you do not intend to extract. what difference will it make if the bees eventually hew the line? By then, the wax will be stiff enough to handle and should be well attached to the frames.