I tend to agree with Marokai here; particularly regarding the fact that the Veeps 'tie breaker' tends to discourage the Senate from being deadlocked. It's one of those 'you'll miss it when it's gone' scenarios.
As for the initial bill in splitting the ticket and therefore the election, I can see the attraction. But what would a VP candidate campaign for? They are a constitutional necessity; it's a low key and often thankless position. However with any executive office holder, the VP has the authority to be an active participant in Senate affairs.
I could only envisage a split being beneficial if we developed the VP into a 'head of government' with the President as 'head of state'...but I'm sure we've had that discussion in the past