The preview looks quite interesting. I especially appreciate that many of the various ancient magic systems contain instructions on how to integrate that system with Hermetic theory and the consequences of doing so.
In addition, the introduction also contains an extension to the Original Research rules that may be of interest to Yair and others who participated in the Original Research go-round when HoH:TL first came out.
https://forum.atlas-games.com/t/original-research-rules-in-5th-edition/499/1