I've been pondering this for quite a while. While the 2x on gas and 3x on groceries is nice with Amex Everday, especially considering no AF, I still value the 5x I'll be getting on gas through Freedom (for at least the first three quarters) over 2.5x in MR because of their limited decent transfer partners.

My current setup is similar to yours:
CSP/Freedom - Dining, travel, rotating 5% (gas most of this year, and dining next Q)
Discover IT - 5% if others exhausted (might happen next Q with gas and dining in the bonus category)
PenFed Cash Rewards - Gas backup, international backup
Delta ST - Only way I earn DL SkyRupees now.

Amex Everyday will probably end up in my wallet, but in the backup section.

I've slowly been considering switching to cashback only cards and then just putting all my cash back in one savings account from all the programs. Once Arrival has Chip and Pin I might switch to that as my main card, and use Amex BC, Freedom, and IT for all the various categories.