Hmmm…
You seem a bit conflicted. 
And I’ll argue that your sandbag work can at least contribute to hip mobility. It seems like it would be hard to pick it up if you can get down there.
Granted, you may not concede top end strength to improve other things, but it seems you still see their value.
It’s tough to admit, but the difficulty of my workouts (that look easy on paper) are proof that I’ve fallen further than I thought in terms of physical abilities. Sure, I’ve been lifting and look decent with a shirt on, but my true performance is crap. I’ve always been proud of my ability to step on a basketball court, softball field, etc and do well. I think I need to improve my motor (work capacity, cardio endurance) to get back to where I truly want to be.