Quite likely you'll have the best D tandem for years, but you've lost your best scorer.
There are no heir apparants inn the minors.
How will we score any goals?
I'm not gonna come up with a few fantasy moves to answer that, because it's all fantasy after all :p
But what I do know is that it would give us an identity. Lots of offense generated from the blueline. Given that both Ekblad and Subban are RH, you could basically have one of them on the ice at almost any given time.