Thanks for the response guys. I wondered this when i was rereading the PHB and nothing was there to stop the possiblity without the need for a thousand feats. By the rules and what I have read (note I am not referencing them), drawing an arrow is a free action if you do so for firing it, so the archer could not load a free arrow at the end of the round and take AoOs with it.
An archer with quick draw could draw the arrow at the end of his turn,a s there is nothing to stop him from doing so, of course that a DM can rule that drawing yet another arrow would make for too many free actions in a round.
Another possible idea for justificating this to any player showing up with it is that using an arrow with your hands require a very different hold of it than one can get quickly for using with the bow, thus requiring a moe action to draw it without quick draw.
The -4 penalty for improvised weapon is a good one, cpould a player take a feat to offset it? There is no feat dedicated to an improvised weapon category, although i think that exotic weapon should do it. Would it be fair? Possibly so, an arrow is not all that good as a melee weapon.
Thanks for participating guys, I had this thought and had to ask and share you know... my archers from now on are surely going to pick quick draw, thus threatening the area around them!