I'd like to see:
1)The Federation abandon the Flowers for Algernon Treaty and start using cloaking devices.
2)Ship artificial sapience seems almost unavoidable in the context of the 24th century technological development. Computer software is clearly capable of a self-organizing intelligence that is human in quality (ala the Doctor). I'd also like to see ship artificial sapience NOT envy humanity, but prefer to explore the possibilities of its OWN existence.
3)The prohibition against genetic engineering becoming subject to increased scrutiny and protest, with the science reborn under a cloud of controversy.
4)Slipstream drive and transphasic torpedoes deinvented.
The techs in 1-3 are not new, but rather abandoned, and this despite their incredible usefulness.