100% agree with you.
Bitshares comes to mind as an example and solution of a decentralized exchange relative and in comparison to Bittrex being centralized.
it is indeed a point of security in preventing the opportunity for abuse at the expense of others. That being said - i think we can have hybrid sort of models. In my opinion DPoS - delegated proof of stake is a hybrid model.
The beauty of DPoS is cooperation is incentivized in a way which promotes effective system functioning and network security.
steem and bitshares blockchains are practical examples
arguably - the issue with bitshares exchange thus far is it's volume - liquidity - coin availability - individual I think at this point - it's not well enough understood and is kind of a 'what comes first question - the chicken or the egg?"it is so ingrained into our thinking based on the nature of all our predominate systems of exchange to have a centralized model of government - it's like we humans almost don't know how to function as a decentralized trading platform exchange yet effectively.
shapeshift and blocktrades are interesting models - perhaps a decentralized exchange could function best like that but with the users collecting the fees...actually as i talk this out - this is the point in functionality for bitshares is that each person has a membership account and that you collect a piece of the fees....maybe not quite 100% aligned...i don't yet got full knowing of all function-ability of bitshares - i'm still fine tuning - but i really do think it's the kind of examples needed for the best benefit of all users of crypto exchanges.
I second the point where people don't know how to function as a decentralized trading platform.
They expect someone, like a government, to put out the laws and rules for them and then they will start something.
Fully decentralized systems are probably difficult to achieve but a hybrid model has all the bright future in front of it. People just need to understand and assess their risks properly.
ARK - is a coin that could play an interesting role in the future as it bridges blockchains together - making for ways of decentralize exchange. i think we are going to see a lot more ways of decentralize exchanging popping up - which is great!