Maggies just don't have the dynamic range to fill such a large room, as you've discovered, even driving them with copious power. Fortunately for you there are many more traditional speakers that can provide greater dynamic range and more broad coverage with a larger sweet spot.
I was going to suggest the recently reviewed JBL HDI speakers as candidates to audition (
@gene @shadyJ I can't find the review on the main site to link to, where is it?), as an example of a speaker that will image well over more seats and have the displacement to rock the whole room if desired. Perhaps counterintuitive, in such a large room you may find that speakers with controlled directivity like the JBLs (or JTRs previously mentioned) to throw a more convincing, enveloping soundstage, across more seats, than even the maggies from the sweet spot. Done right (proper placement and orientation in the room), they really put you "inside" the music.
Also, be sure to audition before you buy if at all possible. Coming from speakers that inherently lack any box and associated boxy resonances/colorations, you want to pick something that also lacks such tells. That will typically limit you in the realm of the Revels, high end JBL, and other well engineered speakers.
Despite the fact that you have gobs of watts on tap, you probably should aim for more sensitve speakers to fill such a large space, to avoid audible tells associated with overpowering less sensitive speakers.
