If anything, he gets way more credit than he deserves.
He is completely carried by Ehrhoff and not only does his play show it, the stats do too.
Christian Ehrhoff is 2nd in the league (minimum 10GP to cut out outliers) in Corsi Relative at 27.3, meaning he is the single best driving force behind possession on the team this season and one of the most important to his team in the league.
The telling stats are
With Or Without You, though (database is a bit behind but still useful).
The Sabres with Ehrhoff on the ice generate 48.8% of the Corsi events, while they generate a measly 38.3% without him.
The Sabres generate 50.4% of Corsi events while Sulzer is paired with Ehrhoff (roughly 80% of Sulzer's ice time this season), while they only generate 25.4% of events with Sulzer on the ice without Ehrhoff.
The Sabres with Ehrhoff and without Sulzer generates 48.6% of events.
So, tl;dr:
Ehrhoff is a dominant creator of offensive chances.
Ehrhoff's numbers show almost no notable improvement when paired with Sulzer (+1.8%).
Sulzer's numbers are massively improved when paired with Ehrhoff (+25%).
Conculsion: Sulzer is a marginal talent carried by a dominant one.