I'd love to see some meeting between the Replicator and the Surface Replicator.  The Surface Replicator lacks the ability to make geometrically precise arrangements...it is all about probabilities.  (What is particularly annoying is that when you ramp up the "try to fit this many in" high enough to fill up most of the gaps, it also begins to violate the spacing limits, meaning you have objects replicated inside each other).

The Replicator lacks the ability to drive it with a texture map or otherwise move away from the simplest of array shapes.  (Plus it won't follow a surface...)

My latest project for replicators was an outdoors audience.  With a painted map I could define seating areas and even aisle space, but getting the chairs to be more-or-less evenly spaced and in rows....

That, and both replicators could use an instance weighting scheme.  Making multiple duplicates of the higher-probability objects is only a stopgap.