Well, you could solve the amplification problem, but to what end?
Front and center speakers are intended to present a coherent sonic image - to precisely place voices and instruments in space. QS8s are designed to diffuse sound into a broad area at the expense of imaging.
Plus, while Axiom design emphases response curve families (how speakers respond and measure off axis), it still optimizes frequency response to be nearer the speaker's axis.
So, you know, whatever you like, but there are design principles that indicate most people will be happier in the long term having tweeters pointed at their face.
bibere usque ad hilaritatem