I have an issue with giving the Borg a massive domain of space they rule uncontested filled with millions of Cubes, and the ability to go nearly anywhere in the Galaxy with impunity.
You make a stupidly overpowered foe? Fine, but either factionalize them (with all factions hostile to one another) so they keep each other in check via endless faction wars, or have them be in small number with each vessel totally on its own and unable/unwilling to call others for help so there's absolutely no chance of ever seeing two Cubes at once.
You make a stupidly overpowered foe? Fine, but either factionalize them (with all factions hostile to one another) so they keep each other in check via endless faction wars, or have them be in small number with each vessel totally on its own and unable/unwilling to call others for help so there's absolutely no chance of ever seeing two Cubes at once.