I'd like to see some more incentives than just bronze, silver and gold (and the for me unobtainable perferct score) in the Daily Challenge.

I find I lose some interest when I realise I am no longer able to reach 22500 and gold, which can happen in round 1 already. Some more levels would keep my interest peaked, if I knew I could reach them with some effort.

So, instead of the 22500 limit for gold, and whatever it is for silver, why not introduce some intermediary levels? It should be easy to understand, so keep the silver, but let 20000 be rewarded as "Silver with gold streaks" or something like that. 24000 could be Gold with rubies, or something exclusive. And instead of the bronze, that most people can get with their eyes closed, introduce something like this:

10 000 - Copper

12 500 - Brass

15 000 - Bronze

17 500 - Silver

20 000 - Electrum (silver and gold alloy)

21 000 - White Gold

22 000 - 18K Gold

23 000 - 24K Gold

24 000 - Platinum

24500 - Ruby

25 000 - Diamond

By all means, keep the old records, and introduce a new "medal cabinet", and let players choose which version they prefer. That way, you won't antagonize anyone who prefers the current system. You can recalculate retrospective the results for players who'd like to see what the finer grained results yields for them.