You gave me something to think about and I tried some things out.
I will show you a sneak peak ;)
I can promise that I am working on something and it will look like this;
You will be able to load a spritesheet, select a folder to save the textures, and then select the items you want from the spritesheet. The new name and ID will be defined automatically but a popup will let you modify them if you want to, if not just press "ok" or "continue". And then you will be refreshing the assets (I am working on this right now). And you should be ready to go in a few seconds.
But I have some other things in my agenda before this, so please stay tuned :D You will get this improvement in the near future, after 2 or 3 more updates before this.
Thank you for the suggestions and I hope you find my tool useful to you!