I would give it a 6, if I'm just judging based on everything I have seen. Square's conference was ok, I actually liked the "frame" gimmick and they showed a lot of games I was interested in, but a lot of them looked a little rough in one way or another. I'm not entirely sold on the titles they did show.
Microsoft was way worse than last year. Like, way worse. Which is sort of weird, I get that they might want to have a "buffer" year in-between now and next gen, but considering Sony wasn't there they should have had a lot more exciting things to show. Even the third party selection was significantly worse, the only ones that looked cool were Elden Ring and Tales of Arise, but the former didn't show any gameplay and the latter barely showed anything.
Nintendo saved it. They had the best E3 conference I've ever seen. Though, I guess they could have announced one more new title. Because really, while there were A LOT of cool game reveals, most of them were smaller third party ones. BOTW2 was the only big one from Nintendo, maybe Mario and Sonic too but I don't think that I'm the audience for that game. Maybe having just one more reveal would have been nice but still ... 10/10 conference.