It was a waste. The problem was that the biggest WCW star's contracts were with the main Turner company and not the WCW entity, so they could stay at home and get paid their millions without doing anything. If WWF had honoured those deals it would have disrupted their existing wage structure which they weren't willing to do and that's assuming Hogan, Nash etc would have even been willing to not just ride out their existing deals.
Instead they rushed ahead with the Invasion angle and instead of Hogan, Hall and Nash we got Buff Bagwell and Chuck Palumbo etc. By the time the big stars' deals had run out and they were ready to sign new ones with WWF, the storyline had been running for ages and it had got convoluted and boring by then.
It was still pretty exciting at the time, Shane McMahon showing up on Nitro was an amazing moment and Booker T putting Stone Cold through a table for Jericho to become the undisputed champion was cool. We eventually got Rock vs Hogan and all that stuff but you are right, in hindsight they did blow it.
