Although they do assimilate, rather than innovate and create their own technology from scratch, they do improvise. They do seem to be adept at applying their technology in creative ways. Mimicry? Perhaps to some degree.
Their core drive to assimilate at all costs is inherently flawed. They made it their sole purpose. Once they've dominated every sector, then what? Would they then step back, say "it is done", and then blow up the whole universe? Or would they simply exist, waiting for something new to come along from the wake of their destructive forces? Regenerating indefinitely?