Even though the double wedding isn't what everyone wanted or hoped for, I think what's important here is not the wedding, but the marriage. If I have to sit through a double wedding so I can get 15 episodes of wedded bliss for Olicity, I'm going to take it. Far better than waiting in my opinion (which - let's be real - we could've waited till the end of the season).
Anyways, I can't wait for Olicity steal some WA thunder ;)
Also, I may add that it bodes well for us that Oliver/Felicity aren't wearing traditional funeral clothes at the wedding unlike Iris/Barry. And we all know what the EPs said about that couple this upcoming season.