I think there has to be a distinction between on-air product and business model. If you want to say a company was the worst from a business perspective, it would be WCW in 1999 and 2000 when they lost tens of millions of dollars or ECW that couldn't pay its workers for the last year and a half on a consistent basis.
From a television standpoint, it was absolutely dreadful sitting through Nitro in the Russo era... about as painful as it is sitting through TNA in the Russo era. I have also never been a fan of ECW TV from 1997-end. All that magic Paul E. created in the early years was gone.
From a match quality standpoint, that is subjecive since the X Division has always received a bunch of praise... except (surprise, surprise) when Russo was booking. The 2005 shows were generally praised as a whole from Meltz and on the net. In 2006, I have more matches on my 2006 MOTYC set than on the 2005 set and I didn't select any of the matches either.
I think John's statement about sums up TNA. A company with a buttload of potential that has pissed a shitload of money away.
Also, XPW is the worst promotion I have ever watched... just abysmal, Juvi or no Juvi. Whoever said MLW may have a strong case as well.