New large customer X wants feature Y. Your product does not currently Y. What do you do? It's hard to say "No." Especially when you have growth to maintain, revenue targets to hit, VC to please, etc.
To me, "opinionated" means "have a vision of what the product is and isn't" (that is strong enough to counter-balance sales pressure).
At a few of the start ups I've worked at, "no" wasn't in the dictionary.
It was always a dumpster fire, the product had some many configurations and options. There were entire sections of the apps I didn't know existed. I think that all these features are ultimately what killed the start up.
At one point I (developer) had to go on a call with a customer to tell them no because the PM didn't want to disappoint the customer.
Learning to say no is extremely important for startups.
Integrating can be tricky, but having one tool try to do everything usually means it does nothing well.
Ideally we will see more effort spent on straightforward, opinionated tools that allow integration. That’s my hope at least.