Double the woofers and you would have to double the internal woofer section cabinet volume. The speaker would be HUGE.
Even if you could, other than increasing power handling a bit, you wouldn't gain much. You could not use them in parallel to increase the sensitivity of the speaker since the sensitivity of the resulting woofer section would be too high to match the mids and perhaps the tweeters.
One of the major reasons you see multiple woofers in other designs is that woofers in this size range are normally around 84db sensitive. So you use two in parallel in order to increase the sensitivity to 88 - 89 db or so. In this case, the Satori 7.5" woofer is already 88db sensitive. So there is no need to use multiple woofers.