the idael part would be if every exchange could use the same UIA, but like above stated, you would have counterparty risk for the otherpartys and this could lead to a downfall to the whole system in the future.
- i feel at the moment bitshares could be the layer above all the exchanges going to use it and for the enduser it is nice, because you only need to have one wallet for many exchanges.
if you think that poloniex, bittrex, kraken etc. would be running on bitshares, you would not have this concerns, because they are coming with liquidity.
on metaexchange we are trying to solve this problem with providing our own market makers. we will add UIAs in the near future to our concept. we are adding fee sharing with METAFEES to our
model to raise more capital and give our investors incentive to talke and use us.