The reasoning from WotC feels contrived, always has. Keep popular cards unbanned because people like them even though they're better than many of the cards that are banned? Sure, why not? Keep those same weak cards banned? Yep, don't want to shake up the format. Also we have a bunch of direct to Modern, high-power sets coming out multiple times a year that will inevitably get some random card banned out of Delver again and create completely new decks. But, you know, community sentiment or something. I'm not sure there is any higher level analysis going on.
And I think that is actually the case. Look at this from Fury's ban in Modern: "We believe the removal of Fury will widen the format, allowing players to explore additional strategies, especially with low-toughness creatures. Finally, fewer overall Rakdos Evoke decks in the metagame will also likely reduce the total number of Grief and Orcish Bowmasters players will encounter."
It has been nearly two months since then and no new "low-toughness" creature decks have popped up just the same decks that have been around for awhile like Zoo, Hammer and Merfolk. And these decks are at about the same play rates post ban too. But there was a cry from the forums, those players hated Fury because they thought it made Infect or whatever pet deck they had unplayable. But that wasn't true because those decks were just bad, Fury or no Fury. That seems to be the reason it was banned, rather the the much more obnoxious Grief. Will there be any reflection on this? No, I don't think so. I think WotC will just ignore that fact and not change the way they approach these things. Randoms online will continue to whine about whatever card they lost to or is unfun and Wizards will continue to listen them, they themselves admitted as much.
Honestly, I have no idea what R&D is thinking these days. Why print a reskinned Cascade in Discover? Cascade has been problematic ever since Alara block so why would they do that again? Why print a card so similar to Bloodbraid Elf? They had to ban that very card in this announcement. These actions do not seem like those of a wise steward.
So I suspect we will never get Mana Drain back. Or Earthcraft. And definitely not Recruiter. I really thought with the Mind's Desire unban we would see more unbans on some of the more reasonable cards but maybe that's just the obligatory unban once every few years.