I was wondering if the coffee would mellow with aging...one suggestion if it's still not up to par might be to wait until the FG is reached and then add the coffee.
Also pale chocolate (from experience with a buddy's porter) is really subtle, so that might have left the door open for the coffee to come through more than expected. Would a dark LME have helped at all?
Bottled/Fridge: Sierra Nevada Celebration
Bombers/Growlers/Aging: The Abyss, Firestone 19th Anniversary Ale
Coming Up: something spiffy, most likely