I agree. Shabbos meals with similarly aged members of the opposite sex is a good idea. However, I disagree about judging someone by the conversations at the Shabbos table. For instance, if I am at a Shabbos Seuda seated next to an Am Ha’aretz, I will probably discuss whatever he is interested in discussing (usually sports) . Maybe if I sat next to you, we could have a long heart to heart discussion about Klal Yud, Halacha Beis, rule Gimmel of the Chofetz Chaim. It takes two people to have a discussion.
However, I don’t think Shabbos meals will solve the problem of pickiness. It will mitigate it by allowing the “rejectee” to avoid the pain of being rejected by a picky person.
A big advantage of the Shabbos meals as a first date system is that there is no “research” before you meet the person for the first time. “Research” into potential shidduchim is a huge source of Lashon Hara. If a superficial person decides in the first 10 seconds that they don’t want to date someone based on appearance, it is hard to argue that there was “Toelles” in telling them Lashon Hara about the potential shidduch.