My position is that he's an overall upgrade over Gomes. Considering a WAR difference between the two this year of 2.6 and -0.1, that's not far-fetched. Even if Guerrero had given back half of those runs defensively by not spending most of his time at DH, he's still an upgrade.
It should be pointed out that if Gomes were in the AL, he too would have been a "DH for a reason." I'm not saying Guerrero is a great fielder. I'm saying he's no worse than Gomes but he's a better hitter.