The G is just a skinnier Huey with two extra rocket pods...
Probably a good reason to release the G first. Minor changes from the Huey, add more capital for future development, then develop TOW capable Cobras.
Remember, the ED Partner/3rd Party devs are still learning how to use ED's SDK, which is a reason most of them are starting with simpler aircraft (i.e. older aircraft and trainers) before jumping into the proverbial modern avionics deep end.