According to the developers they were very influenced by
oldschool strategy
titles such as Heroes of Might & Magic, Warcraft and Civilization as well as board and card games.
Overall, I'm pretty happy to see another game in the same veign as Superstars Tennis (It's being developed by Sumo, who created both Superstars Tennis and some of the more recent Virtua Tennis
titles), and beyond that I'm most stoked about seeing some
oldschool SEGA characters see the light of day again.