There is nothing stopping you from upgrading a character pack that you find lacking. Some people do not like certain fetishes, and do not want to look through them even for the sake of completion. I will generally try to throw in one anal and BDSM image into my packs if I happen to see a nice looking one while collecting other images, but I will not go out my way to find one if I didn't. And again, that's fine if you want to add images into a pack. No one will be offended that you added a dozen images to a character you happen to like and found lacking.
That said the only category that actually matters is Profile, as this is what a player will be looking at 99% of the time. Other images are only seen if you click on the daily report details. While people may do this initially, I have a very hard time believing anyone does this after the first couple months. In fact, if I can't find at least 7-8 GOOD profile images for a character I often scrap the pack or demote them to random status. Having a character with 10+ images in every category may seem awesome, but your average player will never look at most of them and all it does is serve to bloat the download sizes.
Also do keep in mind that some less popular characters barely have any 'normal' images to use, nevermind fetishes. Beast and Preg category images in particular often do not exist. The biggest conundrum though is Pregnant. Once a character is pregnant in game, the Preg category takes over for Profile. What might of once been a nice selection of a dozen Profile images might become one Preg image. Thus the dilemma to pack makers: do you include that one pregnant image for the sake of completion, knowing that it actually downgrades the overall experience OR just omit it?