Hi Jon -
FYI, I wouldn't have called my car's stumble "slight". It was really jerky - you could see engine RPM drop & jump on the tach when it happened.
My understanding is some minor "stumble" is considered normal by drivers of Honda's lean burn engines.
But, no, it's not difficult to remove the EGR valve (2 12mm nuts) or the EGR plate (3 12mm bolts, and 2 12mm nuts, one of which is finicky and the other is particularly tricky due to clearances). FYI, I did it without a shop manual. I do have a moderate amount of mechanical experience though.
If you're intent on investigating anyway, I'd try the "soaking the EGR valve overnight with WD-40 " trick first, as it's the easiest to try.
See:
EGR valve cleaning, instructions please - Insight Central: Honda Insight Forum
If that doesn't work, proceed to the EGR plate removal/inspection/cleaning if needed.
See:
ERG Plate Removal/Cleaning - With Pics - Insight Central: Honda Insight Forum
I did them both at the same time because I felt like diving in, not because it was necessary (the valve was apparently fine).