I have 183K miles on my Blazer. Notice that braking effort is higher than I would like. Checked rear linings and find very little wear, yet I've replaced front pads twice in 100K miles.

Question is, how does one address what seems to be an unbalance between front and rear braking? Looks like the rear drums are not doing much. Drums look very glazed, too.

Does the proportioning valve come into play here? Is it adjustable?

Everytime you reverse, you rear brakes adjust themselves.

It is common for the rears to last a lot longer than the fronts.

60%+ of the braking is handled through the front brakes at any given time.

If you are finding the braking hard, check the vacuum hose going to the master cylinder and make sure there isn't any leaks.