The thing about toaster is that it's one of the few weapons with which you can have a reasonable hope of hitting someone who has the high ground, because of the amount of "bullets" it shoots. You need to button-bash a lot harder with other weapons. I also like that it's a rather short range weapon, so the kills you get with it are more often due to good prediction than random bullets that hit.

On the other hand, there's no reason why you'd need to have a toaster power-up per se, seeing as non-powered-up toaster can server the same function just fine. I'd strongly advice all level makers not to use seeker power-ups, unless their level has a really quirky lay-out, to somewhat reduce the importance of the air factor.

(If you think timing-reliant levels are fun, you could even consider making a rather small map with no power-ups at all, but much ammo.)