Mainly driverbase, but also the appetite for another full CC season. The gap between S11 and S13's editions worked fine so I should think it will be okay.
Yeah its easy to forget about that in a way (just the one season gap between CC1 & CC2), I think looking at the bigger picture now since we know that theres no GT7 this year that its GT Sport or nothing league wise for the rest of 2021.
Though trying to keep things fresh at this stage is pretty much impossible to a degree, I guess for arguments sake you could have 2 more CC's by the end of the year but of course that relies on a want for it from all of us as drivers, I think potentially revisiting old series could maybe now be considered or failing that just have everyone throw there own ideas & concepts into the mix.
One thing/idea I thought of recently was to do single seater again but via the potential of creating a kind of Formula E series using either the RB Jr or SF, the main premise behind it would be simple a 40 minute timed race (FE races use a 45 minute race countdown), one set of racing tyres and no refueling allowed (basically to mimic the battery powerlife a FE car has), the fuel modifier would have to be high enough so that your forced to have to save fuel to make it to the end, (some thing like lasting 75% of the race distance in mix 1 - that way you simply can't keep it in mix 1 the whole race, as the drivers in FE races have to lift and coast a fair bit.)
I know that kind of racing probably isn't everyones cup of tea but thats what Formula E races are about in real life ultimately, anyway the RB Jr has similar speeds to an FE car however the SF has overtake which could mimic the power boost that is seen in that series, either way this is just an new idea I've come up with but I'm sure others will have there own.