First, welcome to iNaturalist! We’re so glad you are here!
Yes! I agree that it is often easy enough to get to genus, but hit a wall with some species if particular details are not captured. I wish guides were keyed out with this in mind, rather than using obscure and technical (sometimes unavailable) categories! I’ve marked down several genera in my region to make just such guide posts on a (hopefully) forthcoming blog, but this would be a great project for a wiki. Or in conjunction with a multi-access key, like was recently proposed. :D
Until I am familiar with a particular taxon, I just try to take more pictures than I think are necessary. I’ve lucked out and caught diagnostic features I was unaware of, but led to an iNat ID. (The magic! The magic!)
What you are suggesting would be a great use of the iNat taxon pages. Right now, the About section generally prints the corresponding Wikipedia article, which I appreciate. However, since we have this great collection of nerds, it would be awesome to have information that assists in refining IDs. As in, the image recognition gets you to Phiddipus, and when you click the taxon page, it tells you (among other things) that it would be a good idea to take a picture of the chelicera… and then tells you what the chelicera are, and helps you choose your own adventure to a likely species.
Some of the hinderance to this is the necessity of expertise and the complexity of range. I can speak to how to key out some species in Montana, but can’t give advice with certainty on the same genera in different ranges. So, it would take a community to get that going.
But… let’s do it! How else are we going to make a nature-aware culture if we don’t make it as easy as possible to learn??