I've read personals that sort of end with "submit your application" or "I'll review your application to determine if you're worthy of my attentions" and many more likened to those- and the ads are not presented as if a role play. I totally wonder if anyone writes to them, or rather if it's what some subs actually desire. None the less, it's always fascinated me.

Finding a compatible relationship, regardless of what style, is all about seeing if there's chemistry... and yes, through questions we discover answers and commonalities.

I'd keep the questions very broad. Much like you've presented. Personally, I wouldn't want someone asking me in a first conversation the details of my sexual proclivities. Whether seeking a dominant or a boyfriend, it just seems a little too much right out of the gates.
But how long I've been interested, my involvement within a community, my overall desires (as in 24/7 vs service oriented vs only in the bedroom vs etc) seem broad enough whilst still being able to determine levels of compatibility.

Mostly, I've just never approached seeking a d/s relationship any different than a traditional relationship.

Interesting topic.