This is the way to go. People will know they are taking a calculated risk with a startup, if you get to know their industry you will gain a better intuition about their use cases (and in particular ones they haven't thought of yet).
Definitely avoid highly regulated verticals at first as they will drown you with security/governance requirements before you even get to their lawyers. Meanwhile get to know these frameworks and what will be expected of you if you want to approach them in the future.
From a feature-set perspective, any large company is going to want to see management interfaces with single sign-on, at least basic roles (read only, billing, ops). Customer should also be able to do everything via API that they can via UI. You should have good audit logs and be able to push them or let the customer come get them. If your architecture supports it, most large customers would like the option for a dedicated tenant instance.
Definitely avoid highly regulated verticals at first as they will drown you with security/governance requirements before you even get to their lawyers. Meanwhile get to know these frameworks and what will be expected of you if you want to approach them in the future.
From a feature-set perspective, any large company is going to want to see management interfaces with single sign-on, at least basic roles (read only, billing, ops). Customer should also be able to do everything via API that they can via UI. You should have good audit logs and be able to push them or let the customer come get them. If your architecture supports it, most large customers would like the option for a dedicated tenant instance.
Good luck!