Yeah, Sega games could use more cross-overs. So far the only team that's really taken advantage of cross overs is AM2 (OutRun car in Afterburner, Afterburner plane in Fighters Megamix (in fact ALL of fighters megamix), Jeffy/Sonic in Daytona USA, MJQ Jazz Bar in VF5, Ghost Squad in Afterburner Climax ETC ETC ETC).
Would be great to see G make an appearance or at least get a mention, maybe some kind of nod to Dr Curien or the Mansion as well. Hell even just having some music from HOTD1 during some fights would be nifty.