That being said, there definitely are some chesronos to singles’ events (and particularly speed-dating). The biggest pitfall is probably the one that Friendinflatbush pointed out – that it can lead to the guys (in particular, but perhaps the girls too) being more focused on chitzonius and to comparing girls.
That is why I don’t think it should replace shidduchim but should only be used in addition to shidduchim for people who have already given shidduchim a fair shot. I don’t think it should be done too often, but if it’s done in moderation, I think it can be successful.
I think that this problem is much more likely to occur with speed-dating. With Shabbos meals, it is the least likely to be a problem. For one thing, you can just have one or two girls over at a time. For another, when you are interacting with someone at a Shabbos meal for 1-3 hours you are more likely to be focused on their conversations than on their appearance.