2-3 months per update. Considering the majority of makers use HS or KK, taking longer seems like a commitment issue. Doesn't mean that it's okay for hand-drawn stuff to stretch though, see what a legend and summertime saga for what a scam looks like.
MO-DE-RE-TION. A game with no challenge is pointless, might as well watch a gallery, but a porn game that's too hard is a turn off. Like holy knight Ricca is almost perfect, there is some challenge but it's not bad if you are not hamfisted.
Anal. I used to be neutral towards it, but the last couple of years saw a HUGE influx of anal, to the point where it is now more common among new art than vaginal, and it grates the hell out of me.
So it's the sequel to the guardian? Guess I will know to avoid the game. The guardian was legitimately the first WEG I finished angry, not going to bother with anything related to it.
Good animations > Good stills > Bad animations.
Making good animations is hard and takes much longer, and if the artist doesn't go for the needed effort you get something terrible instead of good enough still