E3 2001 was my most anticipated E3 by far as I figured the Cube was going to be Nintendo's big comeback from the N64 and things would get back to "normal". When it happened I remember thinking "where are the third party games"? I think it was Rogue Leader and a Phantasy Star Online port and that was like it. Yeah, that initial "uh oh" gut feeling I had was pretty on the money. Then we had Spaceworld and Zelda's visual transformation and by launch my confidence in the Cube being the Nintendo comeback was pretty weak compared to the fevered hype I had had from Spaceworld 2000.
E3 2001 didn't really have anything bad, aside from initial Luigi's Mansion impressions that suggested the flagship launch title was a weekend rental, it just lacked things everyone hoped to see like more third party titles and a Mario game at launch. At the time I was most excited about Pikmin since it was the new IP. One of my favourite Cube titles so that feeling was justified.
Spaceworld 2000 suggested that the Gamecube would have cool "non-kiddy" titles like Too Human and a really great looking "mature" Zelda game and would be online and have lots of great games from Rare including a Perfeck Dark sequel and then look how over the next few years Nintendo destroyed all that hype. I know Too Human and Rare jumped the shark but we don't know that then. At least Rogue Leader and Metroid delivered on the hype.