The plunger is the most common problem,you're right.
I try to install a metal fence post or t-post along side of the hydrant for support.
One thing that doesn't help is many are plumbed in with plastic pipe, and plastic adapters are terrible.The gravel added for drainage helps quite a bit and is a neccessity.
3/4" brass street 90 into bottom of hydrant, 18" galvinized nipple into that, then a PVC FIP or something similar, wrap the whole thing twice with 20 mil pipe tape up to ground level but skipping the brass body, then set the whole thing on a good sized rock or brick, put pea gravel in, then cover it up. If it's a 2' bury instead of 4' or more, I will drive a steel stake to ground level and tape it the entire length with the same tape.
Over kill? Probably.
1. When I say a PVC FIP of some sort or another. NEVER did I use just a plain PVC FIP. Worst case I use a Sch. 80 FIP with 2 ALL Stainless Steel hose clamps on the threaded end. My dad has been doing the 2 All SS clamps on underground FIPs as long as I can remember and to date we have not heard of any leaking.
What I have also done is put a metal coupling on the end of the nipple then screw in half of a 3/4" x 12 Sch. 80 PVC nipple.
2. These days I will put a 24" to 36" leader of PEX on instead of the galvinized nipple. What do you think about that?