Nobody *can* answer this with any degree of assuredness since they have no idea what any given DM will throw at them at any given level. I imagine some DM's will throw archers at their PC's more often than others. I do have to wonder why you think missile attacks become rare beyond low levels. This commonality that you insist is an absolute is actually quite subjective.
And even if it were absolute, and such attacks were rare at best, it wouldn't address the issue of sound mechanics. Rather, it would just decrease the value of the feat without regard to whether it was well-balanced or not. And if that's the case, then either make the feat both balanced and applicable to a broader set of circumstances or just drop it altogether and come with something else to give monks at 2nd level.
Yep, there's a rather annoying thought process at work: anything that players don't make wide usage of must be inherently weak or non-viable in some way, and therefore needs a big boost in order to make more players fall in love with it. I've seen that mentality expressed again and again with 3.5e--be it with a race, a class, a specific feature of a class, a feat, or something else--and it seems like the designers don't stop to think "you know, maybe there are reasons why this race/class/class feature/feat/whatever isn't as popular as other things in that category that have nothing to do with how powerful it is", or "hey, maybe it's okay that not everything has widespread appeal for its raw utility, as long as the game as a whole has lots of viable options".