It would make easier for citizens to have a unified / centralized public admin system, an idea suggested by Martin (Uccle)
Brussels communes now have different administrative procedures and competencies (e.g. diff. ID cards, diff. police units, diff. regulations, etc). It would make easier for citizens to have a unified / centralized public admin system. It would also be good in terms of scale and capacity of the public administration to be more centralized and powerful.
In general I believe more centralization would be beneficial for the whole country even if this goes against the political agenda of many parties.