Was experiencing exactly as detailed above, if going up uphill in high gears there was a very pronounced lugging/hesitation of the engine. It was very annoying and after researching here I had the DME reflashed at the dealer. I thought it worked but realized it was still there after hitting one stretch of road I regularly travel that always triggers it. It wasn't as bad as before, but gradually got worse.
I took it back to the dealer and it was diagnosed with a bad pre-cat O2 sensor. Replaced that and problem solved, engine felt noticeably stronger in that RPM range. Now? I wouldn't say the issue is back, but there's a definite hint of sluggishness at 2,800 - doesn't do the pronounced lugging but just seems to hang there slightly instead of pulling through the range evenly.