Does Absorb replace Sinister Sabotage now?
It depends on your build. I played around with a deck that follows the current meta build, and there you would play Absorb. You can also play a version with Sabotage, where you rely more on the surveil mechanic, in combination with cards like Disinformation Campaign (Vert runs that version). I would say both are viable, which one is better is hard to say though. It also depends on the meta, if there's less hyper aggro, then Absorb is less needed, and the surveil 1 is much more powerfull. Also the casting cost is more easy on Sabotage, it might mean you could run less shock lands. Since the amount of fast aggro you meet (especially in Bo3) declines after 1-2 weeks of a new set, the surveil based deck might actually be better right now.
Here is my esper contral, doing not to bad in bo1 in an aggro meta, but doing average in bo3.
I think both my sideboard and my use of it can be improved.
I don't think you can run 1 build for both Bo1 and Bo3, they are 2 completely different games. Assuming from the SB you will want to play Bo3, I would agree that you don't need to run 4 Moment of Craving, best replace those with 2x Cast down and 2x slots for other things, like 1 more Teferi, 1 more Absorb (or go for 4x Sabotage, and replace 1x Reborn for 1x Disinformation Campaign). I also found that running 3x Azcanta (and then running only 3 Teferi) helps the consistency of the deck, having an Azcanta in your opening hand is just extremely good, and even a 2nd later on is not a total waste.