I realize that alot of addons don't exist simply because they're not possible to do. The information or functions they need to work aren't supplied by the game and so on. This is also the reason alot of nice addons have become useless, like the old Healbot (which if you ask me made things a little too easy though). This special addon I have in mind probably falls into one of these two categories.
Alot of people spend alot of time farming stuff in WoW. You basically just run around and check the minimap (or some other kind of map if you use an addon) for that yellow little dot that tells you you've found a vein/herb. Unfortunately this is a lousy way to spend your time playing. You don't actually do anything fun in the game (unless you happen to feel that finding yellow dots is hilarious) and you can't really do anything else either, since you have to watch that damn minimap for yellow dots the whole time. If you wish to read or watch a movie/series while doing this, you have to interrupt it every 4 seconds to check the minimap. Blizzard loves that you waste time like that, semi-playing. You pay just as much for that game time as any other game time of course. Just as with travel times and the like. They have removed alot of these time sink holes (in the old days you had to spend hours farming mats if you raided for example), but farming is still tedious and boring.
Therefore I would totally love it if there was an addon that simply played a little sound whenever a yellow dot appeared on your minimap. A little "bing!" or something, to notify me that there is something to herb/mine. That would make yet another of those boring parts of WoW a little less boring.
So, if you happen to know of an addon that does something like this, please tell me! Or, if you happen to be one of those cool guys who knows how to write addons (assuming this kind of addon would be possible at all, which I don't think), and write it, please tell me too!
Got any other ideas for addons that would be nice? Remember there's a difference between addon and bot though ;P