I have to question the assumption that a party faced with a tough solo encounter will blow there encounters and dailies early on, then grind it down with at-wills.
Wouldn't it make more sense to open with a leader daily that boosts the whole party for the rest of the encounter, then 'feel out' the foe with at-will attacks and use utilities and healing reactively to keep the party going. Then, as you've sussed out the solo's weaknesses, bloodied it (so you now know about what it'll take to kill it) and manuevered and used powers to give advantage to the heavy hitters, bust out the high-damage dailies towards the end? Seems more tactically sound - or at least, efficient - /and/ more dramatic.