That's not a very good idea, since the swap is there, in part, to allow slightly smaller drives to be resilvered. Say 3TB-10KB instead of 3TB.
I saw someone post here not too long ago that this had changed. In the past, drive sizes weren't standardized, so a "100 MB" drive from Seagate, for example, would not necessarily be the same capacity as a "100 MB" drive from Quantum. Apparently the manufacturers have now agreed on a standard, so that a "2 TB" drive is going to be the same reported capacity, whether it's a Seagate, WD, HGST, or whatever. I remember seeing a link supporting this, but I'm not able to find it at the moment.
If capacities of modern drives are more standardized, a large part of the rationale for the swap partition goes away.