Yes, it irritates me that they cannot wear boots and shoes.

I think that they should have made special foot gear for Khajiit and Argonians like bindings or straps or something. But anyways, in Oblivion the problem got fixed. Someone mada a mod once that was called Boots for Beasts for Morroiwnd. I got really excited and downloaded it. But when installed, it just gave the stats like as if the beast was wearing boots but their feet were still bare to look at - what a rip.
IF it irritates you enough, you can make your own 1 of a kind Race Khajiit or Argonian where you take the mesh for the normal beast foot and copy paste an armor boot mesh over it, but it comes out weird looking and that is then the beast's foot - always wearing that armor boot. Lotta trouble to go through. I'm glad they can wear them in Oblivion.
As for the looks of the feet being long, I don't think they are overly long because of the way their whole body is balanced and positioned on the foot.