I really wouldn’t worry about a genre getting neglected. Jack’s fairly aware of how the votes show what the supporter base is itching for, and he tends to change up his own nominations to reflect that. He’s even mentioned possibly doing themed months in the future to get some new fetishes like futa finally featured.
As for length, while I’m sure we’d all love for the shorts to be a little longer, that’s just not feasible with a monthly release schedule. Frankly ought to count your blessings to get 12 4-6 minute animations a year, considering how long others can take to produce one. And that’s on top of producing a longer film series in the background the entire time.
Also do keep in mind the dude is going through college education in the middle of all this. This isn’t his 24/7 job.