I had an idea for a two-way center channel design that might work. Many of the 2-way center channel reviews here have shown the inherent weaknesses in the approach. Here's how I want to approach the weaknesses. Instead of using a typical tweeter and crossing over in the 2khz to 3khz range, and see all that directivity beaming from the woofer below that, I would use a 2-inch mid-range instead of the tweeter. This would allow a much lower crossover, in the 600-700hz range, which would alleviate some of the woofer's struggles.
The next approach I'd like to try is swapping out one of the woofers for a passive radiator. This would sacrifice some power handling, but would add some low end extension and would reduce the amount of horizontal comb-filtering that two woofers aligned horizontally usually gives you in the 800hz to 3khz range. The only horizontal alignment would be the woofer and the mid-range/wide-band driver, and the lower crossover point would alleviate that relationship.
The one major sacrifice is the mid-range would struggle with the last audible octave, sloping off and beaming, but I posit that this highest octave is non-essential in center channel usage.
Thoughts?