Could even be used for effect... "One of those lizardmen over there just marked you. Which one? Well, can you tell the difference between one lizardman and the next?"
Hmmmm... I see your point but I wouldn't play it like that. It's be pretty obvious which Lizardman was gonna try and shish-kebab you if you take your eyes off him.
D&D has historically been pretty easy on people who are outnumbered. Compare to other games like GURPS or even Exalted, where you can basically only defend from 1 or 2 enemies at a time, and the others get (almost) free hits on you.
I agree 100%, hong. And, honestly, I don't think that's a bad thing for DnD. After all, your party's usually outnumbered or outgunned. That's been true from way back in Basic and 1e. And Exalted's system is supposed to work better in duels, IMO, which is also a good thing. I honestly do think flanking rules will make up for 1 Mark at a time in 4E.
What I should have mentioned is the other, far more deadly, combo: Defender/Striker. Fighter Marks enemy, Rogue flanks... ouch, much bigger ouch than 2 defenders whacking away, particularly when the Rogue does it again next round without pain of reprisal unless the bad guy's willing to soak whatever the Mark does to him.
Well, that would be on a power by power basis. I suspect a lot of fighter and paladin powers will be melee-only whether the mark the target or not (since ranged powers are more of a striker/controller thing), but probably a few won't be -whether any of those include marking remains to be seen.
Ah, very true, glass, shoulda thought of that.