Slowly raises hand...
I implemented the "dealer of death gets all the XP" house-rule myself during my 2nd Edition AD&D campaign. For around a year, no less. I began using the rule as a way of making sure that characters who took zero risks were not going to advance at nearly the same rate as those who regularly risked their lives in combat (seemed important at the time).
The system worked, too. But it worked TOO well. For the most part, the MUs, Clerics and Thieves could hope to gain XP from a monster only 'after' all the Fighter-types had already been killed--which was pretty ghoulish.
To fix the system, I complicated it. I began awarding XPs for casting each and any spell, and for successfully using Thieving Skills--amongst many others XP awards. This seemed cool, at first. More spells were being cast, etc. But it soon became clear that the Fighter-types still retained a significant XP-advantage over time.
So, despite all the helpful rules added to the "dealer of death get's all the XP" system, I eventually abandoned it.
Here's a list of my reasons:
...because I was spending too much time making notes about every lock that was picked, spell that was cast, etc.
...because it was too much work for me to write adventures in which every class had the opportunity to advance at the same rate
...because of a particularly ridiculous situation in which a character got all the XPs for killing a huge dinosaur, and all he did the whole protracted battle was throw one measley shuriken when the dinosaur seemed on the brink of death
...and because it began to seem a little unsettling to me that whenever a monster was on the brink of death, all the PCs would swarm it like a school of pirahna. Heck, even the frail MU would rush-in to whack at it with his staff!
If your DM is trying to make sure that heroic PCs get more XPs than PCs who play it safe in his campaign, then perhaps he could divide XPs evenly, THEN award bonus XPs somehow?
BTW, when anybody complained that a homerule sucked, I always dropped the rule or modified it, which helped keep things fun for everybody.
Tony