I hope its a bug but it seems that the shop no longer has a guaranteed uncurse scroll.
If the level is a mirror level you know that they'll be a crystal chest room on each side. You get one crystal key but 4x chests initially to choose from. Once you open one you know that there will be a mimic on the other side now, so 2x the crystal chest reward assuming you kill it in time, one from the key and one from the mimic. The point is that it's a rare level spawn but you know you potentially get 2x the crystal chest rewards. As for the boring exploration, it's not like the levels are big is it.
Another idea occurred to me, this time for a rare level spawn if that's something that's even possible. The gist is that the level is a reflection design, with the up and down access in the corresponding mirrored halves. The level always has crystal chest rooms, one in each mirror half but a single key. Opening one of the chests makes the corresponding chest in the reflection side into a mimic chest.
You'd know better than anyone else as you presumably can see the stats of depth achieved vs number of games etc, it's my perception (admitidly totally based off assumptions with no evidence) that there is a hump before people get to grips with the game, which was what my suggestion was aimed at smoothing. It may well be that adding such a feature would devalue the first success when it comes through too.
I know that for new players the learning curve can be quite steep, would it be an idea to give players either a starting kit with maybe an identified uncurse and identify scroll, or healing potions, or maybe enchanted starting weapon and armour? Once you have won and ascended you no longer receive it, the 'are you sure you want to continue' dialog when you start ascending can say that returning to the surface will end the starting buff.