You may right in the point of liquidity , IEO in big exchange has a chance to get more investors and attentions but, you miss very important point, what about the projects run IEO, will you participate in the project because it is run on big exchange?
I should check the project carefully, not all the projects can success even in big exchanges.
And in the other side you can find very good projects could not run IEO in big exchanges, so it may go to small exchanges one.
Exchanges never make the projects success.