Vader in the WWF

One of the things we have heard over the years, is that Vince liked guys who were good at doing promos. That said why when he was in the WWF did Vader never get to cut a good promo? I know Cornette did most of the talking,
but even in WCW when he had Harley Race as his manager, Vader always cut monster promos on WCW Saturday Night or other shows, it helped get him over.

Did no one in WWF watch Vader in his time in WCW to know this? Would he have been better off on his own and not have Cornette? Do you think in their primes, Paul E. or Bobby Heenan would have been good managers for
Vader?