I'm sorry, but I can't help but read that as "limit alliances to the size of my own alliance bloc". Lurian bloc members demanding a limit of 33% when their own bloc forms almost exactly 33% rings obnoxious to me, doubly so given they were what caused these alliance blocs to begin with.
Sorry, Chenier, this proposal's been on the table since long before the current Dwilight status.
If there's any particular situation that prompted it, it's the Cagilan bloc on Atamara.