I can't remember but with your market research did the new take on slivers get viewed as a positive or negative, mechanically I mean, I don't care about the art, but a big fan of the change, wish they were all like the new cards.

Mechanically, players preferred the change. I’ll tell a story to hit this point. Many years ago, we ran a promotion called “Selecting Eighth Edition” where we let the audience vote on which of two cards to include in the next core set (Eighth Edition obviously). One of our biggest votes was Crusade vs. Glorious Anthem. Crusade is a card from Alpha that costs WW and it grants all white creatures +1/+1. Glorious Anthem is a card from Urza’s Saga that costs 1WW and it grants all your creatures +1/+1.Crusade had been out of the Standard for a while and the card is pretty powerful, but development had decided it was okay to bring it back. Rather than just put it in the set, we decided to let the public vote it in. We put it up against a card that was similar but powerwise weaker. We were shocked when Glorious Anthem defeated Crusade. We did a little research and started finding more evidence that many players didn’t like it when their cards helped the opponent’s creatures. And when we dug deeper, we also discovered that less experienced players weren’t even aware that your cards could help the opponent’s creatures. Why would your card do that?So we decided that we needed to shift how we thought of lords. Slivers got changed later because the first time they came back after the shift was Time Spiral block and we felt that it would be wrong in a block all about nostalgia to change them then, so we decided that the next time we brought them back we’d make the change.As I mentioned in another post, the original plan was to give them a new creature type, but we ran some internal playlets with people outside of R&D and we kept getting the same comment. “Why aren’t these Slivers?” So we changed them to Slivers.

You've talked before about the push to reduce board complexity by phasing out cards that make players have to look at their opponent's side of the table to know what's going on with their own cards (e.g., Crusade as opposed to Glorious Anthem). If that is the case, what's the deal with Arcane Melee?

The default is to have cards only affect your stuff but from time to time a spell is more interesting if it affects everyone. Note that Arcane Melee is a rare so it has very little impact on board complexity especially in limited where, on top of everything else, it’s not a good spell.