I was going to get all the replays I wanted before posting here, but since the discussion picked up in pace, I can't help myself anymore. I agree with
lskildum that hard match ups should not equal bans, but only if it's limited to a few types. Mega Metagross
tilts the match up for MANY types without having to change its moveset. You can build Metagross-Mega to specifically annihilate almost any one type easily and a few with a little more work, but with something like Zen Headbutt, Grass Knot, Bullet Punch, and Ice Punch (which is what I use), you have the edge against
Fighting,
Dragon,
Flying (Magnezone trapping for Skarm/Celesteela), and
Ground (trust me, makes things way easier). On top of this, I'd like to mention Steel's inherently favorable match-ups which are just further exacerbated by Metagross-Mega:
Ice, Rock, Poison, and Fairy. Not to mention the types Steel already has a good chance at beating without Metagross-Mega, like
Grass, Bug, and Normal. And that's all with the same moveset I use. Other options include Hammer Arm, Earthquake, and Thunder Punch, which adds a layer of unpredictability to this Pokemon. You've all seen the calcs of Metagross-Mega tanking a myriad of attacks, so I won't get into that, and I'm hoping to get replays of Metagross-Mega in later, but I just wanted to jump in this while it was hot. There's also Metagross-Mega on Psychic, which does something else entirely, but I'm admittedly not very familiar with it there.
And now onto Magearna! I think I wasn't very clear before, but I now I want to paint a clearer picture. First of all, Magearna has a GODSEND typing along with great bulk. On top of this, it has a colorful movepool consisting of
Aura Sphere, Thunderbolt/Volt Switch, Dazzling Gleam/Fleur Cannon, Flash Cannon, Energy Ball, and Ice Beam! You can cover a lot of Pokemon with those moves, and you may be able to get away with a turn one sweep against a few types with unprepared builds by using
Shift Gear to allow Magearna to outspeed up to Scarf Garchomp with a Timid nature. The ability to boost its speed sharply in tandem with its colorful move-pool and Soul-Heart makes it a VERY dangerous Pokemon, capable of sweeping types on its own from turn one. While it has the ability to sweep at turn one, I was just using that as a way to illustrate how helpless a type could be to Magearna. It's more prudent to save Magearna as a late-game sweeper as it can nab boosts easier against weakened foes.
Aside from Shift Gear, Magearna also has access to
Trick Room, which is arguably just as effective as Shift Gear, allowing Magearna to "outspeed" everything, but in a different way. Using Trick Room also allows Magearna to dump its speed EVs into HP instead, further bolstering its bulk, and Life Orb, optionally, to make its attacks hit even harder. Trick Room not only makes Magearna a solid sweeper on its own because of Soul-Heart, but it also lets Magearna support its teammates like Banded Tapu Bulu, which can just about OHKO everything that isn't a wall, and still 2HKO most walls (with SR)
through resist! Trick Room and Shift Gear are not to your liking? Specs and Scarf work just fine! I personally use Scarf and have had great success with it, but most have opted with a Z-stone, and for good reason! Z-Stones allow any Pokemon to drop a nuke any time and they want and this is especially useful for Magearna since KO'ing a Pokemon gives it a SpA raise thanks to its amazing Soul-Heart ability. Let's not mention the fact it doesn't even have to KO a Pokemon directly to gain a boost.. Simply switching it in vs a Toxic'd mon about to die or timing a switch against one of your opponent's sacks to hazard starts you off with a +1 SpA raise.
With Magearna, what we have is a bulky Pokemon with an amazing type and solid coverage backed by respectable power, which is further bolstered each time it can get a KO thanks to Soul-Heart ability, and is made possible through either Shift Gear or Trick Room, the latter of which can support teammates, and is made even easier with Z-stones, but can just as easily work with Choice Scarf and Choice Specs to fulfill different roles.
I'll be working on getting replays for Magearna as well as Metagross-Mega.