in real life - It is a matter of fitting to the women. Some prefer bigger, other somewhat smaller as long as it isn't too small.
I know someone that complained several times that bigger ones cause her pain
Depending on how good a game is otherwise, I can put up with crap like insane dick sizes and other things I don't find very appealing, but I think the best designs always lie within the range of "idealized, but still in the realm of realistic". That goes for penis size, but also breasts, butts, etc.
I was about to make a thread with something similar to this. I was fucking someone a few days ago and it wasn't great so I put my hand near the bottom of my stomach to see if there was any swelling of his dick going in there, as there are in some games. There wasn't, obviously. what I shouldn't have done is ask him if he thought if his dick was bigger it would have made such a swelling.
anyway I wouldn't really want that to happen, it would be uncanny and weird. I hate games where it does and games where it should because the penis is so unrealistic it must create a lump. I hate any proportions that are exaggerated. If i want to flick my nonsene to cartoons I will but If i download one of these games I want the characters to look as real as possible. I played a game a while ago that I was mostly enjoying then one of the girls had areola as big as her boobs. it was so jarring I deleted then and there.
in answer to your question my opinion is too big is unpleasant, unsettling and unwelcome in these games and in reality. i never met one so small it couldn't be overcome with the right mood and a bit of elbow grease.
IRL probably depends per person as above, in games I don't mind over-sized dicks (personally find the stomach bulges hot but they are not required/necessary)-
It does matter. Anything over 7 inches is too much, anything under 3 is too little. 4-6 is the perfect area, 7 and 3 are acceptable. Though it's usually hard to do exact size in art. So it comes down to "is it proportionate" if yes then it's good.