Unfortunately, while it's special to those of you with tiles, the look of the stones and the fact that many of them are dedicated to those who have passed on really does make them feel like a memorial to the dead, which isn't a cheerful way to enter a theme park about the possibilities of the future.
I really think the best solution is what others have suggested: move the structures elsewhere in the park so that the entrance can be greener and more cheerful (I really think Epcot could use a bit more greenery) and, if possible, redesign the stones to look more futuristic and less somber. Something clear, something colorful, whatever - just anything that doesn't look like "tombstones." They could be redesigned into something attractive, rearranging the tiles to use all available space, and turn a negative into something that really enhances Epcot for all visitors, not just those who purchased tiles.