I think both cards have significantly been devalued so it is hard to say. Part of what makes all of these changes challenging to consumers is that Delta is "forcing" tradeoff decisions that may make people uncomfortable.

For the majority of current Delta Reserve cardholders, $75K of annual spend on an Amex card is probably not feasible in most years. So, you're forcing people to decide - fewer rewards and higher MQD earn ratio - or better rewards and lower MQD earn ratio?

For those who can cover >$75K, you're forcing them into having two cards and/or again the opportunity cost of far better earning/reward cards.

All that said, I think many folks do really value the companion fare ticket (for both cards). But if that's the case, I really do think Delta runs an even bigger risk of sock drawering these cards. For the Delta Platinum card, the MQD boost is completely irrelevant at the likely spend levels and earn levels for those cards. So, it's the companion fare and other benefits (MC1 boarding, free checked bag) plus earn on select categories (it's not bad for grocery and hotel.. and tolerable for dining). That actually keeps a strong value prop for a casual Delta flyer.

The Reserve for those <$75K in annual spend that I think becomes a very questionable value prop. The 10:1 earn ratio on MQDs is not that great, the earnings are terrible, and lounge access is highly limited. I assume it will be buoyed by the inevitable offering of one of the choice benefits for Platinum and/or Diamond being lounge access spend waiver.

For those with >$75K in annual spend... it becomes an opportunity cost question. $75K is a lot of spend to put on a garbage card, so people will need to believe it will materially improve their status for the year and/or really, really value lounge access. The ~$1200 value you're leaving on the table ($750 SkyMiles earnings vs. $1700-2000 realistic earnings from category cards or top cashback cards) is a lot to give up.

Trying to mentally balance the tradeoffs just makes me not super interested in managing the complexity and just bowing out of the Delta card ecosystem entirely. Of course, that is probably exactly what Delta wants - card optimizers are not profitable; they want people who don't spend the mental energy and effort to do this and just want people to say "hey, this is helping me with earning status and/or lounge access.. let this be my default card."

We'll see where it lands.