...I feel like I'm missing something here. I have heard many many criticisms lobbed at 4E--some justified, some not--but I can't recall ever before hearing that there was a pacing issue with the adventuring day. In fact, I have always regarded that as a great strength of 4E, that you are not shackled to a daily attrition model. You can have one day with a single encounter, and another day with six in a row, and they both work fine. Maybe you don't burn through all your healing surges in the 1-encounter day, but so what?
(I do remember a lot of talk about "grind" within a single encounter, but that's an entirely different issue, with two main causes. First, people did not understand that they had to adjust encounter difficulty for player skill--a skilled well-optimized party will demolish an encounter that would TPK a bunch of newbies, and there is no way the books can tell you how skilled your players are. You have to figure that out yourself and dial in your challenge levels accordingly. Second, Wizards gave monsters too much defense and not enough offense in the early monster books. Once they got the stats properly calibrated, combat went much quicker.)