I don't think it is, or will, ruin the league. Miami has set the bar, now, I see a lot of organizations follwing suit. Likewise, I see a lot of players trying to join forces with other stars, similar to the CP3 rumblings. Paul and Howard would be close to a "superteam". Point is, the way the league is currenly constructed, if it's in the rules to be able to sign a Bosh, Wade, Bron trifecta, then so be it and I'd expect others to follow.
My main concern with "superteams" being constructed, is the geographical location of teams or the historical teams, like Boston, reeling in all the players. Miami, LA, Orlando, NY...that's where they will be formed. Not Philly, ort Milwaukee...or (gulp) Atlanta.