' In my opinion, if you give a Chansey Eviolite (item that 1.5x defense and special defense to not evolved pokemon) she is better. Also, not sure is Blissey can learn this but Chansey can also learn Seismic Toss (move tutor in gen 1 remakes) which is a 3-4 shot kill in most cases. Flamethrower on a tank wouldn't do much imo.
Mega Metagross/Scizor's Bullet Punch says hi. That's one of the biggest reason why those two aren't used anymore. That and they're annoying af and only there to prolong and infuriate the opposing player.
If you were to see a Scizor come into play you would obviously switch out for Chansey has low defense. Yeah you give up a turn but Bullet Punch wouldn't really make a difference imo because of Chansey's naturally low speed. Its like that for all physical sweepers against Chansey but Chansey can really tank a special hit.
It's useful against Steel types, which as you know are immune to poison. Combining Blissey's flamethrower with Groudon's drought ability and it can OHKO a Scizor. Flamethrower would only be used in a few situations. You can also teach your Blissey Calm Mind, which will also make Flamethrower more useful.
My absolute favorites are a tie between Porygon2 and Regice. I also have many other favorites(pinsir, sudowoodo, magnezone, etc.), but those are my top two. Also Porygon2 with evolite is a beast.
wow, some of you guys are into competitive pokemon =]. nice for my favorite pokemon i would pick scizor. reason=it looks cool and i like the name, scizor.