Most of Vince's best angles in the 80s were stolen from other companies...The Hart Foundation-British Bulldogs feud was his attempt to recreate The Midnight Express - Rock & Roll Express fued, The Bobby Heenan Family was WWE's version of The Four Horsemen, Ted DiBiase was in part based on Ric Flair...The Demolition team was a blatant rip off of The Road Warriors...
Anyway, for an Now angle to have worked in reverse you would two major WCW stars to start the "Invasion"...Sting was obviously huge but he was also well established as clean cut hero type. Remember, Nash & Hall were "tweener" characters who bounced back and forth but were more heel than fan fav so believing they could start the "Invasion" and try to destroy WCW wasn't as far fethched. Lex Luger had only been out of WWE for less than year when the Now started so if we are talking the same time frame that wouldn't have worked, he was just there. Flair had been gone for a few years, he could have been the anchor. Still, he would have needed a partner, someone well known, even if more of mid carder like Hall, it might have been interesting if The Giant had joined him, he wasn't as well established but he had awesome size and great look, Arn Anderson probably made the most sense. Hogan & Savage wouldn't have worked because they were WWE guys before, it would be like homecoming for them (Granted, Nash started in WCW but he never was over, Hall's Razor Ramoan gimmick was a clear take off by WWE of Hall's Diamond Stud WCW character, but that gimmick never got off the ground in WCW and wasn't well remembered).
Once the two WCW guys jumped you would have needed the "Surprise Turn", the shock like when Hogan turned heel and joined them. At that time in WWE, with both Hogan & Savage in WCW, the only guy who was popular enough and credible enough as a fan fav to make the "turn" was Brett Hart.
Now, you can argue that if say Flair & Giant or better Flair & Anderson made the jump and started the Invasion of WWE it would have been as interesting and compelling as Nash & Hall in WCW, assuming WWE played it as two WCW stars coming in to take over the company the way WCW played the Invasion storyline. You can also argue that collectively Flair & Anderson were bigger names than Hall & Nash with wrestling fans in general. However, there is no one on the WWE roster that could have generated the buzz and the heat by turning on WWE in 1996 that Hogan generated with his heel turn, which really took the Invasion to a whole new level. Brett Hart turning on the fans would have been a surprise, and those three in the ring would have formed a far better nucleus from a ring performance stand point than Nash, Hall, & Hogan did, but the shock waves and interest caused by Hogan's heel turn could never have been duplicated by Hart (or anyone else in WWE at the time) because they simply weren't big enough stars. You can argue that in 1996 Flair was bigger than anyone on the WWE roster so anyone who joined them would have been icing on the cake, it wouldn't have made the cake. Hogan was bigger at that time than just about everybody in the industry and was as well established as a fan fav as any wrestler ever was with the mass audience. Hart would not have generated the same electricity.
Could an angle like that have worked...Yes, but it wouldn't have been as big as the WCW version.