Given human propensity to settle near bodies of water (exhibited even to this day), and the change in sea levels after the last ice age, the bulk of intra-ice age settlement artifacts are probably submerged within a relatively short distance from our existing coastlines. I would be personally interested in an effort to systematically investigate these areas.
It would be great to see more underwater archaeology, I'm sure there's a lot to find. But due to variations in local conditions it's really tough to systematically investigate: every site has to be treated individually. Plus doing anything underwater becomes at least 10× harder and more expensive. Human scientific divers can only work easily down to about 30m: anything significantly deeper requires commercial diving protocols, submersibles, or ROVs which raise the difficulty and cost even further.