Well, the eShop's been delayed a week (after the end of May) and I'm not as disappointed as others seem to be. Partly because we were never given a hard date to begin with on when it was coming out (which leaves me to believe that Nintendo had this date already planned from the beginning.) The implications of them releasing during E3 will hopefully mean a better conference experience for us early adopters in the form of possible live streaming, 3DS demos, and game trailers.
Also, I don't think it's a mistake that the release of the eShop and other as of yet to be announced features on the 3DS will be occurring on the day of Sony and Microsoft's press conferences. As was stated above, this delay was also undoubtably part of a PR strategy to steal thunder away from any potential NGP announcements.
I'm quite curious and even more excited now for the reveal in about 3 weeks.