I've been thinking about this for a few minutes, and I'm having trouble figuring out why anyone might want the amount of top heat that comes from a broiler (but doesn't seem to come from any of the ovens used in actual NYC slice joints, like Bakers Pride/Marsal/Blodgett ovens).
There are two main reasons (for me) to use the broiler:
1) Faster bake time: With no broiler, the top won't be done for at least 6-7 minutes. As you know, when you lengthen your bake, your pizza becomes less floppy and more crispy so the only way to go faster is to raise the stone temp and add broiler time to balance the top and bottom so they finish at the same time.
2) Cheese boil: I still need to do more testing, but last night my cheese didn't get a good boil going, and it didn't oil off at all. I personally like when my cheese oils off and creates that orange/greasy look, so the broiler helps me do that.
Deck ovens don't have a "broiler", but they do have adjustable top & bottom elements so you can have a higher top heat than bottom and basically do the same thing as a broiler.
We're dancing around the "Traditional NY pizza" topic here, in the end you need to decide what attributes you like best in your vision of NY pizza and go with it.