I'm a house rule guy, so no judgement here. Did you add this just because it sounds fun, or is there an effect you were trying to accomplish?
My most consistent rule change has to do with multiple melees, though I have not been consistent in doing it. I don't like the one-melee-per-turn rule. I have done one-melee-at-full-Quality-all-else-at-minus-one. I've also just ignored the issue and allowed multiple combats. Once I moved all melee resolution to the end of the turn, but that interacted too much with the activation-and-done idea. My motivations have to do with never wanting a unit to charge into melee without some risk to itself, and with not wanting a unit to be artificially vulnerable. I want a strong unit to be a strong unit, and not suddenly having to take a morale test fighting some goblins because there were two small units of goblins.
Oh, and the one about a hero getting his own defense value. Just roll everything else first.
Haven't been playing with OPR long enough to have consistent house rules, but my son and I are playing around with house ruling melee. I don't have a big problem with melee tying up shooting units that get stuck fighting off a horde of demons, zombies, etc. It doesn't make sense to me that hordes would just back up to let a unit charge back into them or make ranged attacks against them (or other units even further away).
We're currently testing a rule that the winner of melee (i.e. unit causing the most wounds) gets to decide whether the charging unit backs off or they remain mired in combat. This prevents small units of cannon fodder from becoming tar pits whilst allowing larger melee hordes to be effective tactically. We'll update the forums with the results
I've only played a few games so far but almost right away we decided that each miniature would have 2 actions, wether it's move-move, move-shoot or shoot-shoot. Then we came up with a bunch of other house rules for fancy actions and reactions haha