As a side question, why did you not limit your spells/magic items and give the players free reign in 3.5? Almost every instance I see of people having trouble with 3.5 is the GM not restricting things. Instead of having to deal with these over powered things, why give the players access to them in the first place if it was going to ruin your game or make it very very hard for you to manage?
You're kidding right? There are super broken combos right out of the 3.5E core books. Just look them up. Here is a quick example: Scry, Teleport / Without Error, Finger of Death or Phantasmal Killer (preferably with their DC pumped up with magic or magic items to the point of not having a chance to save against it).
Personally I don't want to have to read every book and do a bunch of exploratory math on every supplement and every spell (some in the core game) to tell the players whether they can play it or not. That's not my job as a player, that's WotC's job as a company that is providing the game for us to play.
As to the 5 minute work day, Yes, we already acknowledged that the DM could mitigate it using story means such as random encounters, time limits, other adventurers, monster ambushes (despite them not doing that in the first place), etc...etc... That's actually what this thread is about "The DM will have to deal with this".
Oh and I run between 1 and 7 encounters in a day in 4E, my players never know what they are going to get and rarely complain about being out of daily powers. In fact the great limiter in my games is healing surges running out long before they use their dailies.