I don't particularly agree with cutting Memnites against tempo decks, seeing as how Memnite + Thopter indirectly count as part of your manabase, and I don't like the prospect of weakening your mana consistency against tempo decks. But I can see why you did it against RUG to reduce less dead draws, considering that's what I used to against RUG, so if it worked out for you in your two wins, then keep at it. I haven't tried cutting Memnites since Deed decks were in vogue, but I might revisit cutting mana/Kobolds as a sideboard strategy against grindier fair decks.
How did your actual match against Storm go? I think adding Whipflare is overkill, because your whole game plan is to prevent Storm from going off, and you're only running a 2-of that's only useful in one game state where they take a gamble and ETW on turn 1. You're already removing a 10+ cards from your offense to hedge your Storm matchup, keep in mind you also need a way to win if you do happen to roadblock Storm.
Why would you take out Etched Champions against Miracles? Your point on taking him out leads me to believe you think Etched Champion is used for defensive purposes, when in fact, he should be deployed as one of your scariest, must-counter threats.
While Rest in Peace doesn't conflict with Chalice@1 like Relic/Cage would, I'm still skeptical as to how anyone could consider Rest in Peace to be an acceptable answer versus dedicated gy decks, as in Reanimator, not Loam. It's 1W, so you can't naturally cast it (let alone have backup against Daze effects) off of Ancient Tomb, and it's 2 mana, so if you plan on casting it turn 2, it might already be too late against Reanimator.
I noticed in most of your matchups your sideboarding usually involves cutting Signal Pest. Why keeping running him if he's going to be a dead card in a lot of matchups? He dies in an embarassing fashion to Baleful Strix & Vendilion Clique, makes Jitte counters much more brutal, conflicts with your Chalice@1, makes RUG's
Rough / Tumble more of a blowout... the list goes on. I came to this conclusion at the last minute before a GPT, and I cut the Pests for SFM + Batterskull (made top 4 btw). I haven't looked back since.
Ensnaring Bridge seems like a good idea. I've always known about it, but I never bit the bullet and tried it against Sneak-Show because I thought it was too narrow against one matchup, but it's something I might consider testing against Elves. You are right that Elves can answer Bridge with Viridian Shaman, but Ensnaring Bridge does some time and could allow for a strategy of just sitting on Bridge and trying to drain your opponent with Tezz's ultimate.
I think MDing 'tech' cards like Chalice/Revoker/Canonist is a short-sighted decision. Sure, it may randomly steal game 1s from combo, but you might also lose winnable games against fair decks that could've been won if you just went all the way aggro.
I definitely agree. Keep on playing Affinity!