What if Philip Duke of Auvergne survived which means Auvergne, Boulogne, Burgundy, Flanders and Franche Comte remained under personal union, would this burgundy be better than OTL or would it be any different.
hmmm A surviving Philip of Rouvres could be interesting. Furthermore there is no dispute about the status of Burgundy ITTL, it is not an appanage and it can be inherited by/through the female line in the absence of (direct) male heirs. This goes all the way back to the settlement between duke Robert I the Old of Burgundy and his brother king Henry I of France.
Also this dynasty is much more distant related to the kings of France. Also the position the OTL Valois dukes of Burgundy had in the Low Countries came from the match of Philip the Bold with Margaret of Flanders and John the Fearless (their son) with Margaret of Bavaria (-Straubing, the branch with possessions in the Low Countries)..