What so many seem to forget is the number of times the Mediterranean has dried up, or partially dried, and the effect that might have had on migration to and from Africa. When sea levels were dropping to around 400 feet lower at the ending of the most recent Ice Age, rafting across Gibraltar or from North Africa to Sicily would have been much easier. Then there are other discoveries like Denisovans, and Flores “man” to further raise questions that there are more answers to be discovered. The eruption of Toba around 74,000 years ago really put a dent in population, as can be seen from the much fewer human finds from then until around 50,000 years ago, when more humans appear to have left remains. There was also a noticeable dip in world temperatures around that time.
This next link to ancient temperature changes has at least one chart which very clearly shows the severe drop about 74kya which lasted for nearly 10,000 years before there was a significant increase of temperatures until the final relatively steady decline to around 24,000 years ago. That low level lasted until the sudden rapid increase starting around 18kya. For those who have discovered the studies of Firestone, et al about a possible major bolide event in the Northern Hemisphere around 13kya you will note the sudden drop for about 1,000 years known as the Younger Dryas half way up the rising temperature line.
There were clearly multiple waves from multiple origination areas to multiple destination areas with substantial intermixing.
The Neanderthal love tour of Europe is one example.
Vikings and Celts are the result of that.
There was no Toba bottleneck, more recent searching for verification of the *hypothesis* turned up evidence that was clearly not true.
The Mediterranean last dried up almost 6 million years ago, then refilled over 5 million years ago, in the Zanclean Flood. Subsequent drops in sealevel occurred worldwide due to glaciation, but by that time humans had been using watercraft for 100s of 1000s of years.