I think it's something like
If one or more tokens would be created under your control, those tokens plus an additional one of those tokens are created instead. ?The additional token gains haste?
Took "of those tokens" from Primal Vigor and restructured the sentenced based off of Allenal, Chatterfang, etc. I think Jinnie moved "instead" to the front to make the two options more clear.
I'm not sure if the haste part is crystal clear as worded. I know what your intent is, but
Flameshadow Conjuring makes it
super clear what is gaining haste.
I do wonder if you should specify creature tokens. The haste clause makes it feel like it's for attacking tokens, not to try to immediately pop a Blood or Clue. Naya colors are also more focused on creatures.
"If an effect would create one or more tokens under your control, choose one of those tokens. Create a token that's a copy of that token. That token gains haste. Sacrifice is at the beginning of the next end step." ?
I wonder if
RGWGW
Doubling Season token text.
Tokens you control have haste.
At the beginning of your end step, sac all your tokens.
3/4
Is good?
TL;DR I don't know precisely how to word this.