Full progress can be seen by visiting my Repo
As we have a full body that we are putting clothes on like a Barbie doll, I decided to make an alternate set of clothes. Instead of doing it after the fact, I am doing it along with the course. She has no toes, so sandals are a no no unless I modify her feet. Here are her heels.
Oh good idea!
I love the shoes! 
It was a modification of the boot. Ripped off all the up the leg faces. All but the center line on the top of the boot. Adjusted the sides so it had slight coverage of the side of the foot. Extended the top of the center line to make an ankle strap. Narrowed the heel. I did run into a problem with the heel as the thickness modifier started to leak out opposite sides. I just scaled it a bit larger as I didn’t want to make the shoe thickness any thinner. I could have broken the heel off into a separate object and not applied a thickness to it. I think it came out great.
I think you’re thinking correctly. 
Not all shoes for the warmer months need to be full-on sandals. I think the shoe you designed is perfect as it gives a nice “cool” look for the summer without having to show off the whole front of the foot, such as the toes.