Hi Dave, have somethings in mind and would like to share and have your opinion.

I just swaped back the sierra1 drivers on my sierra2 upgrade years ago and i cant believe how lovely they sound. Over the years, i think i had become more sensitive to mid and high frequencies and and the sierra 1 provides a rounded presentation with a less forward midrange presentation. I also like to add that dome tweeters seems add some sweetness to the music, possibly the roll off at off axis over the wide dispersion raal.
With the sierra 2 EX out, have you thought about the combination of the new midbass drive and the standard dome tweeter for people that is looking for more warmth on a speaker. Something that is more forgiving perhaps.