The interesting upshot of Mr. Clegg's argument is that his proposals will likely produce a different outcome than expected, an example of fixes that fail. Assimilation is always conducted and governed by the people with power.
Assimilation is a filter, which by definition subtracts.
It subtracts from the people who don't hold power to reduce the variability in the group that does hold power. The long-term consequence is not a celebration of our collective riches but the conversion of everyone to a selected set of approved riches. Mr. Clegg appears to be arguing for the one best view of things. Diversity suggests that we seek to find the broadest view of things. This is where learning and insight become possible.