Steve, reading the details that you now have of this horror story, it seems clear that although you can replace damaged drivers or an entire speaker, you can't replace your and your wife's lost hearing. Since obviously she doesn't do this, allow me the liberty of yelling at you: "turn the damn thing down!" Seriously, you should use a SPL meter to monitor the levels that you use. "I like it loud" isn't(or at least shouldn't be)an acceptable standard for determining safe sound settings.
The amplifier in your 7200 is quite powerful and the 100 watt rating is a typically conservative one from HK. A quick search found
these lab measurement numbers for the essentially identical amplifier in the 7300. You don't need a new receiver or, except for replacing the damaged items, new speakers. Yes, it's unusual that only the mid-woofers in the VP150 would be affected, since the far more delicate tweeter voice coils typically are damaged first. Also it seems that the M22s would have been damaged at that time.
I'll again mention the possibility of using an M2 center, which can do an excellent job at typical listening distances and safe sound levels. See for example
Dan's M2 vs VP150 report .
