To be slightly pedantic, one might call this situation over-architected rather than being purely over-engineered. I would agree that over-architected solutions (regardless of the internal engineering quality) are definitely hard to alter due to the many disconnected disparate parts, not to mention any human/political boundaries that have grown up around the implementation.

Following along that train of thought, under-architected solutions are often great to update because you get to make logical cleavages that are informed by time spent in actual production use, giving you a much better basis for any decisions.