Your rogue doesn't hit on a 6? He needs to do his job better (pick the right opponent, gain CA and target reflex if need be) - that should do the trick.
Man, that's the truth. We just finished our 20th game session in this campaign and the rogue missed once. We were shocked. We realized we couldn't remember the last time he had missed. It's to the point that he'll sometimes say a number while he's doing his rolling, I'll announce that he hits, and then he'll explain that that's his bonus.
We actually felt the grind early on, when we were getting used to the system. We were kind of worried after playing through Keep on the Shadowfell. However, we have the opposite experience now. My players are all very good tactically, and all have built extremely effective characters, and work together like mad. I like to think of us collectively as power-gamers in a good way.
The party they have right now is a freakin' wrecking crew (swordmage, rogue, warlord, wizard). Unless I've severely deprived them of resources or placed some other campaign-based restriction on them, I usually have to go to the highest end of what they should be able to normally handle to give them a real challenge.
On the other hand, when the combat is effectively over, I call it done rather than playing it out until the bitter end. 2/10 enemies are left, both bloodied, they flee. I usually decide this by having hidden victory conditions for a fight, which the players sometimes have clues that might help them figure it out.
Overall, we're really happy.