There are too many variables to tell.
Are we assuming that the trial in which WWE won the rights to buy the company ended differently and the Bischoff conglomerate ended up owning WCW, and in that case would that have been witth or without a tv deal?
Or that Turner, and more importantly is money, would have been around?
Obviously, a Bischoff controlled WCW without a tv deal or a financial backer wouldn´t have been much of a competitor to WWE, and would probably have been much like ROH.
Same scenario except with a tv deal would have been something like TNA.
In a scenario were Turners money had been around and control of the company wasn´t given to a lawyer anything could have happened really.
Had they put out a bad product, they would still have ended up dead.
If they had managed to turn out a great product, they could have continued competing with WWE.
Heck, they may have even managed to kill WWE.
The reasons WCW failed are many, and a lot more complex than most wrestling fans acknowledge, so it´s really hard to tell what would have happened if one or more of these problems were fixed.
Even if we immagine all of them were handled and the company were running perfectly, it would be impossible to tell what reaction that would warrant from WWE, and how either company would fare in the 2000s when wrestling started to become less popular.
Personally, I would say that considering how many problem areas WCW had, it would have probably been in the spot where TNA is now, considering that a weakened WCW would likely have been struggling to find a new TV deal or sign big-name talent they would probably have ended up on a less popular channel, doing smaller shows, and making less money than the WWE.