I'd prefer a full Black Market. It's how I enjoy it IRL, with all setups on buy (Baker too, and Trade Route does fun things) except Potion.
I don't own Young Witch, but I honestly yhink that it would be hylarious. Just think of the good times if Menagerie is the Bane. But saying goodbye to on-setup cards sounds like a fine alternative.
I play somewhat competitively, but I mostly play for the fun times, and Black Market is more fun when it's whole.
The excitement of turning three completely unknown cards is priceless. If you always know what you can expect the experience is somewhat spoiled (compare
"Border Village! Cool!" to
"And here's Border Village, Scout and Transmute. Shit none of the draw cards yet.")
I've found that it also helps in the seldom situation that somebody pulls a real Bomb(TM) out of the BM. If the BM is finite (and 25 cards is
very finite), it really feels bad for you that didn't get it, but when the BM is an infinite mine of wonders you'll be a bit less screwed, as you might pull your own diamond out of the tunnels. You might still lose, but it
does feel better (I've tried both).
To conclude, I must say that I've felt compelled to "fix" the second shuffle of the IsoGoko Black Market a couple of times before, and it was an unfun chore, so whatever you go for, I strongly support taking that part away.