Ike is truly the best choice, and not because I main him. Ike can get punished easily, which trains the noobs to shield and NOT spam attacks. Metaknight would only cause noobs to spam AUREGEREGEREGA forever. Ike would be slow and teach noobs to use attacks wisely. If you can get good with Ike, you will be able to very quickly master faster chars like Marth, Fox & Gang, etc, but if you start training with the faster guys, you will find that slower characters will be much harder to deal with.