"Please return the signed NDA (no revisions please - we're juggling numerous potential investors and need to be efficient with our time)."
It's unusual to see a "take it or leave it" approach to an NDA, and it's not particularly inviting/welcoming. I understand the desire for efficiency, but when you're onboarding investment partners for the next half decade you might initiate it w/ a more collaborative spirit? It also signals a lack of capacity/resourcefulness. Most NDAs are immediately signable anyway.
Good luck!
