Well, in theory, having it pop up from destroying a health shard block in an adjacent room should already make it not too tough to find now; just from watching other people play the game, I've noticed that alot of them will tend to break those blocks whenever possible once they find out what's inside them. And if you're getting good missile drops it's not too hard to clear out every single one of those blocks on a floor. And the items in the secret rooms are totally worth going after.
About the health shards though.... something extra to add to them: when you collect enough to bump your HP up, your HP also refills. Or something like that (maybe fills halfway?). Does that sound like a good idea, or a bloody horrible one?