The devil is in the details, as with all such things. I wouldn’t categorically refuse to sign it, just like I wouldn’t rush to sign it regardless of the terms.

The main thing I’d want to be sure of is that I understood their measurements and how to achieve them.

Then: Does it protect my freedom to create on my own schedule on the topics I select? Do I retain the rights to my work and can repost or reuse it as I choose? Are there penalties beyond not getting the payment if I fail to meet their conditions?

Medium has been pretty writer-friendly in the past, and I doubt they’d take this opportunity to change that. But intent and perception do not always coincide.