With more and more Cosmic talis and Cosmic 4-sets being released, 6-sets are slowly becoming devalued. There are a handful that are useful, but even these are probably niche.

No way should a 5-set or 6-set EVER be released as a Cosmic (I already think the 4-sets have pushed the envelope too far). That's too much value in one slot. But, Ying and Yang are both 3-Sets... could there be a way for us to have our cake and eat it, too?

I don't think the dropping of a Ying or Yang (3-set) Cosmic would be game-altering. On the contrary, Ying/Yang was the first set I loved when I was just beginning... but I hardly see it or use it anymore (mostly it finds temporary/permanent homes and gets a look in Gauntlet now and then). Cosmic versions of each half would also allow you to get Ying/Yang onto any toon and give you a 2-set to play with. That would be... really cool.

That's it. Simple idea.