Thank you, everyone, for your interest, input and time. My focus on a 2.8 was to use TC's for more reach, effectively carrying more reach with nothing more to tote than a small TC. I've too many lenses in my bag as it is, with more still in the cabinet. Trying to pare down the inventory. I do use wides and ultra-wides mostly for landscapes, waterfalls, etc, but also reach out now and then in other situations. I've found that many times as I await a better sun angle or some movement of clouds, there are other things happening around. Birds or other wildlife. Shooting something blooming and wanting to melt the background away, shoot a portrait shot of my wife or one of my daughters, so on and so forth. I always found the old Ai 300 2.8 useful and fun, though a beast to carry. I no longer desire to tote that load and fiddle with manual focus 100% of the time. Did a bunch of years with a Nikkormat and an F3 and back then it was automatic to me. I've been spoiled now with really good AF lenses and zooms.
Again, thank you all. And I'm no closer to making up my mind now than I was before.