Something I'd like to see for every cryptocurrencies is a Gini index by crypto.
Since a richlist allows to know the exact content of every wallet, it should be possible to get a Gini index out of it. I'd say it is not difficult to do (although beyond my coding skill).
It would not be good for a coin in particular, but for the ecosystem in general and should be global effort - but, hey, I'm here, so I propose it here since the richlist has just been created. Of course, it would not account for people with multiple wallets but that would be quite representative still (especially if we consider that the percentage of user with multiple wallets is similar among cryptos).
Without having done any calculations I will offer a guess at the gini-index for every single crypto: 0.9-1.0 (1.0 is perfect inequality, as in one person owns all the coins).
As you mention yourself, it does not account for multiple wallets, but just as important, the numbers we can get from the blockchain is not wallets, but addresses.
Many addresses will be empty (coins go in, and leave again, meaning it will be empty when looked at in the block chain), leading us to see 50% (guestimate) of addresses empty, thus lop-siding the gini-calculations.
Further, exchanges are accounted for in the calculations as there is no way to leave them out, which will muddy the results even more. I.e. my TEK holdings on Cryptsy should count towards my holdings, not towards Cryptsy's address.
Also, the gini-index is meant to measure income equality, not equity equality.
So, while I am a big supporter of numbers and statistics, calculating numbers that will tell us absolutely nothing seems like wasted effort.