I guess from a sentimental standpoint, everything they have given to this organization, especially Pierce. KG came and changed the landscape of it, but Pierce was here through thick and thin. A lot of fans feel a connection with these 2 because of their heart, desire, etc.
Outside of that, I think it is best for the team, in terms of progression, to move on and try to build for the future now, as we can't win the championship with them as cornerstones of the franchise anymore. If there's a way to keep them around but decrease their roles, and let someone else step up or if there was some way to bring in a big name then I'd be all for it. I don't want to see Pierce and KG move to another team/retire/whatever...but, it looks like that's the direction things may be headed if we can take anything from various reports at this current juncture. There's always that fine line between supporting individual players and the organization as a whole. Going to be a sad day when the two of them hang it up or move on to another organization, but we, as fans, knew that the team would eventually come to this crossroads and have to give it serious thought. That window was supposed to only be opened for 3 or 4 years and they were able to stretch it to 6, albeit I think this year was a mistake in retrospect, but it is what it is. It's been great seeing relevant basketball again, but that's the nature of the beast. Sometimes you have to take a step back to hopefully advance 3 steps forward in the future.