Are the alt yellow alphas a definite no-go? I would question the "low-demand" claim - have not heard much about this set in general until recent days (the post distribution of this thread is somewhat infrequent/clustered)... I imagine a more representative sample would skew that ratio upward a fair bit.
Higher price for an alt kit like that is to be expected, but since it's a relatively unique kit I think many would consider it worth the price.
For me the yellow alphas are the main appeal of getting this set, since currently no other GMK sets have this. We do have Penumbra and Plum, sure, but those are more muted-cheese yellow, as opposed to, well, honey-yellow - and neither of those have yellow mods (for that we have Serika).
With the alt alphas, I am in for Base + Novelties + Alt Alphas + Spacebars + Rama cap, but without the alt alphas, unfortunate pass for me.