It's only possible to assess the current situation. It surely may improve in the future, but it's important for users to know what they are getting into right now.
And of course development on top of an existing protocol is faster than making changes inside the protocol.

Even if they address all the issues and create a real decentralized product, exchanges still will have the overhead of replaying not only the steem blockchain, but also filtering out the steem engine related transactions, which will take considerably more time on itself.

It would have been way more efficient for everyone to develop the functionality in the core. But of course that would have required qualifications few developers have, and wouldn't have allowed for easy monetization of a half finished product.