> we'll remove it if we find data that suggests it's bad
So how about instead of saying "let's have coffee" you look at the accounts of some of these people complaining to verify for yourself the things they are saying (such as "lower conversion")? If you feel Stripe doesn't have the data requires themselves to determine this, maybe asking a few of these merchants to send you a report documenting the sales penalty they experienced? This doesn't seem like a very difficult situation to verify, and it sounds like you will be able to learn something really valuable in a really short amount of time that could affect not just this feature but your entire product roadmap.
The "let's have coffee" line (which you tried to use on me as well back when I was demonstrating API flaws and limitations in Stripe a couple years ago ;P) is really difficult to interpret as a "data-oriented" approach to helping merchants: "let's talk about this in person" almost always translates to "I'm a people person who is good at convincing people of things in real time, so how about we move this conversation from a medium that involves long, thought-through arguments that can be backed up by data to one where we are both forced to think on our feet and operate out if memory" ;P.
> If it's bad, we won't just add an option to remove it -- we'll remove it for everyone.
What everyone here is trying to tell you is that this feature probably works well for some merchants (I mean, you even claim to have tested this yourself, so clearly it must) but horribly for others. Is this really an impossible idea to you? :( The people complaining also spent a bunch of time not "just complaining", but providing reasons why their situation caused the flow to be awkward, and those reasons clearly don't apply to all merchants: in some cases people have even tried to determine "the core difference" (one-shot vs. repeat sales). This would be a great opportunity to not pull a "let's have coffee", but instead dive into the data and specifics of the complaints with the people who are trying to help you.