You focus not enough on what implication it has when items aren't classified well enough.
I understand all that, I promise; and I understand that you have a very specific vision of how clues should work. What I need you to understand is that
Shadows of Doubt is a procedural simulation, not an adventure game. In an adventure game, when you find the one pair of High Heels you go, "Ah ha! The High Heels! This has very specific implications." In this game, it's more like you are looking around, finding a ton of stuff, seeing a field of a thousand suspects, and deciding what is important and what isn't. In this game, shoe styles are not that important and there is not a huge narrative reason for the color of someone's shirt. (Please don't be disappointed that there are many shirt colors in the game, but they usually don't mean anything either.) A pair of shoes may mean something, or it may not - and most of the time it's
probably not. Instead of dwelling on each piece of possible evidence as some huge revelation pregnant with meaning in a single linear path towards finishing the adventure, if something doesn't seem relevant you keep looking around to find other, more substantial ways to locate or identify a suspect.
Again, yes shoe styles COULD be implemented in such a way as to be central to the gameplay loop, but in this case they just weren't, and it's completely okay. It's important to recognize that not everything imaginable can be implemented in a one man project, and shoe style (so far) just didn't make the cut.
It's also important to recognize that while some psychological profile stuff is in the game, it is not as deep and full of implications as you seem to be hoping for. Your expectation of "this man is a transvestite, therefore that means he had lesbian parents, and lesbians always teach kids that murder is good, therefore he is the murderer" or whatever you're hoping to see is not going to happen here. The systems here are limited to stuff more on the level of "this guy likes plants, therefore his apartment has lots of plants".
I reiterate that when actually playing the game you will find that there are so many avenues and angles of investigation to explore, I honestly doubt the design of clues will upset you once you get into the flow. In an RPG that didn't bother to add rock throwing to the combat system, one quickly adapts and forgets about it even if it the art shows rocks on the ground - because the other available weapons are just as fun. Of course, you'll remember this conversation which will trigger disappointment in this one thing not being implemented; but I honestly believe that if your attention wasn't drawn to it here, it's unlikely you would have noticed it at all.