[Executor]

Any thug, regardless of gear, is hardly better than an Asynja. Flat out, due to her good stats and base equipment, she is better (and much cheaper) than any equipped thug raiding vice.

Personally, I don't think any of the Asynja paths are useless,
-more air for a glamor unit is always good, and she has a freakish defense as it is
-earth gives options of protection buffs and more reivnigoration
-blood can be used for blood vengeance
-and the death (least useful path imo) can be used as spellcasters, wailing wind

I agree with what rdonj said, shishis are better price vice but that's because they're far too cheap for what you get.
However I wouldn't call Asynjas hopeless or bad in any situation nor are they worse than other SCs. The glamor they have + very high defense, which can also be increased, + a luck pendant makes them extremely hard to hit. Even an SC with quickness and gloves of the gladiator would have a hard time hitting her, that is if he manages to catch the Asynja.
Sure, lack of resistance can be a problem, but it's a problem for anyone.
The only SCs you can really protect from elemental damage are Tartarians anyway.
Same goes for mind hunt.

Basically, a stealthy, teleporting unit, with great stats and great base equipment that can capture 3 provinces in 2 turns and not even be intercepted by anti SCs can hardly be considered underpowered or situational, but that's just me.