Ok, mild ranting here, so bear with me. We've delved into 4e pretty good now, I think, getting good exposure to the rules and the flow of the game. I've had the fortune of also playing in a 3.5e game concurrently, and it's led to the following observation:
4e combat is slow! I've been talking with various people about this, and there is some consensus. As far as I can tell, there are two primary contributors to the slowness: infrequent, all or nothing attacks, and less damage per round. In 3.5 as you gain levels, you also gain multiple attacks per round, which, eventually, leads to more damage per round. Even the "lowly" spell caster, with one spell per round, rarely missed, and rarely ran out of/low on spells in a single encounter (low levels it was possible, but not typically by level 10+). 4e nerfed the multiple attacks, and in the case of spell casters, the damage capability of those attacks. It did NOT (so far as I can tell) reduce monsters hit points to compensate. In 3.5, it is not uncommon to obliterate all enemies on the map in round one, before they even act. This is IMPOSSIBLE in 4e, in my experience at least. Making every encounter take that much longer, turning every session into what feels like a dungeon crawl (Not something I personally am opposed to, but...). 3.5 also has "lengthy" (5+ round) combats, but that's with the increased party damage! Imagine that fight using a 4e PC...(remember, monster hps are relatively unchanged).
I know Scott has made some effort to lower the hp of monsters in his game with some success, but I have another idea: bring back multi-attack...kinda.
4e already gives us the Heroic/Paragon/Epic tiers, so let's work with those. Heroic I'd leave untouched. Admittedly, in part because I HATE PLAYING LOW LEVEL!

For Paragon...how about 1 encounter power, + 1 at-will power, per round? Or, for simplicity, change at-wills from Standard Actions to Minor Actions? For Epic, allow an extra standard action per round (2 encounter + 1 at-will/round). Granted, I am not looking at secondary effects here, just pure dice damage, but I really doubt an extra 1d12+1d8+xx (the strongest at-will attack...barring maybe a psionic augmented one, haven't looked too closely at those, remember extra dice from sneak attack and the like can only be applied once per round assuming encounter attack hit as well) would severely unbalance things in the PCs favour. It would, hopefully, quicken a combat from maybe 6 rounds to around 3 or 4. It would also give the PCs more to do, as some combos of at-will + encounter, or minor + standard, can have some nice synergy. It has the downside of probably burning through encounter powers even quicker (at say epic levels), but you can still swap a standard for a minor...two at-wills per round. Plus an action point every other encounter...*shrugs*
What do you think?