I don't know how many times has been said in this forum that AIR is a long term coin.
Aircoin can only be alongterm coin if the model can work as the pool grows.
I think it is questionable they will be able to continue to benefit from market inefficiencies to anywhere near the same extent as the pool grows.
So that will mean they will be some kind of Index fund, IIUC, holding a basket of crypto coins. However they still have to pay expenses out of the pool too.
There is no clear plan released how this is achievable, and to get serious investors on board, I think they'd need to explain just how it will work a bit more thoroughly
An index is one possibility, but high frequency trading on other altcoins is a far more lucrative one (with greater gains but far less risk) that will sustain the pool. Index investments however, serve their own important purpose in the Altcoin world. It's one of our next major advances we're experimenting with, and once AIRcoin is a bit more fine-tuned, we'll work on progress on that front.