I don't do the same rotation every time, or even the same weight or reps, I do what feels right for my body that day, so it would be nice to be able to select from a dropdown of available equipment (better if it's filterable), and add total time spent, weight, reps at that weight, how long my breaks were, etc.

It's not useful to me to have to "build a workout" if I don't know beforehand what I want to be doing, nor am I going to remember after I leave what I did, so an in-the-moment updatable thing would be great.