The only issue I see with unbanning Aegislash is that it's still a decent threat outside of King Shield. Until it actually attacks, it's got 150/150 defenses and then after it starts attacking it get 150/150 offenses. Obviously it becomes super frail in Blade Forme, but at the same time it still poses a decent threat in terms of damage, especially if it starts outspeeding things.
Darkrai I have no issues with though since that thing sucks outside of Dark Void.
The thing with Aegislash also is that especially now it's easy to wear away. Unless you're saving it for some weird sort of scarfed revenge killer of the ilk or are bringing it in via a very slow U-Turn or Volt Switch, it WILL be taking hits in Shield form without attacking back. Otherwise, it'll be sitting in blade mode and be easy to take down. It's also really only got two sets now: Physical or Mixed (It's special movepool is just Shadow Ball, Flash Cannon, and Hidden Power and Shock Wave but who would want to use that?). Sure it's got great physical coverage but nothing much else.
Hey, even in shield form it has a 75% shot of being OHKO'd by Mega Lopunny while only having a 6% to OHKO it back. Looks like we have a much better idea of a counter for it now that King's Shield is gone.
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In fact, let's go through the banlist and see who we could unban.
Arceus - No
Blaziken (Mega and Non) - I can dig testing it out. It lacks Protect so it can't easily get a free speed boost and it's other stats are just ok for the job. Also, it lacks Baton Pass too.
Deoxys - Well Defense form is already unbanned. The only other potentially non-broken form is Speed but I wouldn't unban it since it is an amazing revenge killer there
Dialga - No
Genesect - It was never known for its status moves so no
Mega Gengar - Some of its worst sets are gone but it still has Shadow Tag, so it can easily choose its own opponents, so I say no
Giratina - Maybe, but I wouldn't recommend trying it since it still has great stats and a great movepool. I would lean towards not unbanning either form
Greninja - Oh no! This thing can't use Spikes or Toxic Spikes. What do you say? It still has Protean and amazing coverage that got it banned in the first place? Nope
Groudon - No
Ho-oh - It just got ridiculously more powerful now without Stealth Rock and having one source of reliable healing left so no
Mega Kangaskhan - None of its sets are really phased much by this Meta, so I say no
Kyogre - No
White Kyurem - No
Landorus - No
Lugia - Interesting Option. It has less offensive pressure than Giratina even but it is extremely bulky especially with an Assault Vest. I'll say maybe but I would like to lean no.
Mega Mawile - The only thing it really lost is Swords Dance. No
Mewtwo - No
Palkia - No
Rayquaza - No
Reshiram - No
Mega Salamence - It only lost Dragon Dance. No
Shaymin - No
Xerneas - While it lost Geomancy, it is still easy to see why I'd say no
Yveltal - No
Zekrom - No
Altogether, the only other Pokemon I'd be willing to see unban besides Defense Deoxys and Aegislash is Blaziken and its Mega. In the maybe piles are those Pokemon without offensive pressure like Giratina and Lugia, but I would highly stray away from unbanning them. What do others think?
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With the other current topic, Wobbuffet is probably too much for the same reason Mega Gengar is. Wobbuffet can more easily do its job now that everyone will be using attacks on it and the only way to get around it are to use Physical Ghosts, Special Darks, U-Turn into a Ghost, or Volt Switch into a Dark. I don't like this guy one bit if he's going to reduce the playing that much.