I find myself always catching a butt-load of pokemon and I never use them, that's a given when you play the game. However I do catch them when I can. Whenever I see a rare one I catch it. Whenever I see one I haven't seen before I catch it. And then there are those ones you don't want but you get them anyways(Relicanth is super weak to grass but you need one for the Regi's). Nonetheless If you play pokemon you know there are going to be at least(for me anyways) 20-50 pokemon and not use them. Its just part of the game. And as your question on releasing, I absolutely agree. However you Fail to take into consideration the points in the game when you wish you would've raised Poochyena over Zigzagoon, etc., etc., . I have thought the same thing and then fail to remember the Gold/Silver epidemic where even though rock smash is useful and almost neccessary to complete the game in those versions you can only teach it to one pokemon (its a tm). I always end up teaching it to either the pokemon you get before it(sudowoodo) or some other pokemon I don't ever use later. But anyways good question and may luck be with you