ranking of cryptocurrencies becomes outdated in my oppinion, its quite easy to create a currency which has a higher marketcap than bitcoin, but a corrupt sect arround the indexes prevents listening of those.
with the end of national banking cartels a time called "coins of style" will come, in this it will be more about a cryptocurrency and about its management and much less about a pretended selffullfilling ranking.
this could then also help prevent to get the market divided into new marketmovements. that want to free themselves from attention monopolies of established top 10 coins.
etc.
regards
Rankings are always based on the price in the market but i think that the ranks should be based on its popularity because it is always depending on the investors on how the coin will grow in the market.