I'm in favor of this change. I was reading through the official game forums a little and found one paragraph that pretty much mirrors my opinion.
....remember that the whole purpose of these various sets is to actually have players make choices, instead of encouraging "cookie cutter" builds, such as the nigh-universally recommended 3 Piece Borg / MACO/KHG MK XII shield, or 2 piece Borg / 2 piece Omega/JH/Breen builds for weapon proc & hull regen.
When everybody uses the same thing, what's the point? This break-up of the Borg set will force players to find something that will best fit their play style, ship type and career. It might also mean that sets like the Jem Hadar and Breen may actually get used more often, too. I mothballed them a long time ago, but they should be viable with the right build. More so when Season 7 hits.