Worst case senario: One target allows only one attack roll only. Basically it gives you a single chance to make a 2W attack. Pretty harsh gimp of a daily, but might be worth it. maybe....actually you're probably almost better off twin striking. Still, if you're a DM and you feel the rules really mean '2 targets' this is at least a compromise.
Best case senario: One target allows for two attack rolls, take the best result. you get two chances to make a 2W attack. Pretty good for a daily, but significantly less good than it usually is against two targets. Not overpowered, not going to break anything, not going to punish the player, not going to swing the encounter. Its basically just a rolled in Elven Accuracy, once a day. There is NO 'brokeness' reason not to allow this, just a rules one....and the rules one has a few (loop)holes in it (targeting 'invisible' enemies, etc.) While i don't think the 'targeting invisible' enemies qualifies as a bag of rats, it is silly enough that i would say 'don't bother, just attack the one target'.
Stupidly overgood case senario: DM lets you consider the single enemy as both targets, allow two 2W attacks against it. Obviously too powerful. never even consider this.
BOTTOM LINE: While an initial look at it seems to say 'you must have two targets', they are plenty of reasons to allow just one target and not really any reason that its a bad idea to allow just one target. It helps the ranger, whose daily is otherwise not useable in solo fights, and 'punishes/gives-unfair-advantages' to no one. Let it happen.
Best case senario: One target allows for two attack rolls, take the best result. you get two chances to make a 2W attack. Pretty good for a daily, but significantly less good than it usually is against two targets. Not overpowered, not going to break anything, not going to punish the player, not going to swing the encounter. Its basically just a rolled in Elven Accuracy, once a day. There is NO 'brokeness' reason not to allow this, just a rules one....and the rules one has a few (loop)holes in it (targeting 'invisible' enemies, etc.) While i don't think the 'targeting invisible' enemies qualifies as a bag of rats, it is silly enough that i would say 'don't bother, just attack the one target'.
Stupidly overgood case senario: DM lets you consider the single enemy as both targets, allow two 2W attacks against it. Obviously too powerful. never even consider this.
BOTTOM LINE: While an initial look at it seems to say 'you must have two targets', they are plenty of reasons to allow just one target and not really any reason that its a bad idea to allow just one target. It helps the ranger, whose daily is otherwise not useable in solo fights, and 'punishes/gives-unfair-advantages' to no one. Let it happen.