I could be mistaken, but I don't think so. Now that the PCs in my group are fighting Paragon foes, the encounters sure seem to take a longer time. In a low level heroic dungeon setting, we used to easily get 3 or 4 encounters in during a gaming session and now we get about 2.
The Cleric is fairly optimized with regard to healing, so she is not DPR oriented. The Swordmage has Aegis of Assault, so he is slightly DPR oriented as is the Fighter who concentrated on burst attacks and on her bonus to attack rolls, so she hits in about 80% to 90% of rounds (depending on foe level) and often multiple times per round. Our final PC is a Ranger who does focus on DPR.
I definitely see the grind in our game. I did, however, read Stalker0’s Guide to Anti-grind which might help, but his guide does not change the fact that grind exists if one throws higher level foes at a group and appears to exist more at higher levels.
The issue is gradual, but noticeable. Part of it was addressed with the expertise feats. But, part of it is things like monster auras and powers which do more impressive things at higher levels. Stunning a PC prevents that PC from acting for (typically) a round, hence, pushing the encounter out by ~0.2 round. Stunning multiple PCs can easily push the encounter out 2 or 3 rounds, especially if the PC Leader is stunned. Knocked prone and dazed can have a similar effect. Restraining, immobilizing, regeneration, weaken, insubstantial, resist, blocking line of sight, all add up. Enemies that teleport or fly around can make it difficult for melee PCs to get an attack in every round. It's not just a to hit / defense / damage / hit point issue. That aspect of the game seems to be reasonably well balanced, especially with the Expertise feats introduced (assuming the PCs can acquire them or the DM auto-gives them as a house rule). The issue seems to be a number of PC actions vs. number of NPC actions per round issue.
Lower level foes do not have as many of the special powers that do these type of "slow up the PCs" things.
I think it is also dependent on how well the DM runs NPC tactics, how well he sets up encounters, and how well the players run PC tactics. The PCs definitely have a lot of resources at higher levels, but so do the NPCs. I do think that if the DM does not play the NPCs (and terrain) tactically smart, then an encounter can actually become as easy and fast at higher level.
I also see a trend, at least from what I've observed here on the boards, for there to be more Strikers in parties. Action economy seems to be a big issue and by focusing on a single target, multiple Strikers can shift the action economy towards PCs quicker. NPCs cannot do this, or at least not until late in an encounter, due to the number of healing resources most PC parties have.
One place where increased durations of encounters might not occur or the perception of it might not occur is if the DM is not very tactical. Players get good at their tactics because they run the exact same PCs over and over again and learn from experience. The DM tends to have a different set of NPCs to use each encounter, so if the DM is not very good at analyzing his NPCs and playing them tactically smart (and planning encounter tactics before a gaming session is part of this), then I could see where a given DM has the impression (valid or not) that encounters are just as short at higher levels as the PCs wipe out his NPCs as quickly as they did at lower levels. By the time the DM figures out that he should have had the monster fly instead of stay on the ground to be beat on, it's too late.
