Some sort of coloring would definitely be useful - or icons - especially for the "specialization" techs. Maybe a "lock" icon for one that restricts a future choice and a "key" icon for one that opens up a past choice.
I think the "# of turns" information should be added as a suffix to the title of the tech as presented in the trade list. That would give me an idea of how costly a tech is (but not how valuable it is to the AI) to research.
