Exactly as the title says Allow some, namely maybe the first two in each profession, be allowed to be bought with shards. Maybe 30 of them? That's a little less than what it currently is, and people would have to choose between turning those shards to moonstones, but 30 shards are easier to collect, than 25 moonstones, which is 250 shards.
The 30 is just a number there, and I could see it going up to like 50 shards? Starting people don't really have the bones or bonepaste levels to turn that many into moonstones, so it would feel less like a time gate. Just some early morning thoughts. It also would give some more power to moonstone shards, which, people do underestimate as a currency overall.