On Mental Misstep:
Honestly, mental misstep is what keeps the meta interactive. Otherwise we would have players goldfishing on both sides of the table more often than we do now. (Storm doesn't need to be better.)
I like MM keeping restricted cards like ARecall and 1cmc tutors in check outside of them being restricted as well. Unfortunately, MM is necessary with all the 1cmc cantrips in existence at this point.
My 2cents anyway.
Duress effects will not get better with the restriction of MM. Duress effects aren't as good now because we have so much draw available than before.
the decks that run Karn, don't necessarily run MM. So, Duress could be used against them, except Duress has to happen before the taxing effects come down on the other side.
If Narset goes unrestricted and MM gets hit instead, Narset isn't going to be weaker. Duress here won't do much either. Decks running Narset have the big blue draw engine already to stay ahead.
Duress and effects like it, are weaker now, not because of MM but because of the powerful card draw available now. Let's face it, Duress effects are huge tempo loss in most decks now, unless they can win on the spot. (DPS/ANT)
Not only that but we have Collective Brutality available to us, which dodges MM and it's more versatile.
In the case of Dredge, Force of vigor/Negation would be more at fault for its current strength, not Misstep.
Also, Deathrite Shaman is doing just fine in the current meta. Doesn't look like MM is keeping it oppressed.
Oi, this card used to be compared to Mana drain and as such, competed for slots in blue decks. Spell pierce is purely defensive, where MM can be proactive as well.
One of the main reasons Flusterstorm took the spot over pierce was simply because you can be more aggressive with your plan than you otherwise would be if you ran Pierce or other narrow counterspells.
If MM needs to be restricted merely on the grounds that Pierce and Duress is not played anymore/as much, then Flusterstorm should follow suite because it pushed Mana Drain out, as well as suppressing strategies relying on mostly instant and sorceries.
I hope I expressed myself well enough, apologies if I didn't.
I'm a bit under the weather but had to post my thoughts before they're rendered irrelevant by tomorrow's announcement.