I shoot primarily architecture. Mostly large commercial projects - schools, commercial office buildings, interiors and sports venues.
Right now, I shoot using my 5D MK2, and for the majority of the time, I use my 17-40L ,70-200L F/4 Non-IS and 50mm f/1.8 always from a tripod. Since the perspective control in Lightroom has been getting better and better, I find myself using my 24L TS-E Mk1 less and less. I know that there are strengths with using the manually controlled perspective control lens, but over the last year, I have developed techniques that allow me to not need it as often.
My question is this - instead of having the TS-E on a shelf gathering dust, I am considering trading this out for a high quality prime lens of about the same value - $750-850. I have most of my focal range covered, except for 40-70mm. At this point, a Distagon is probably out of reach, but maybe a 14mm f/2.8 Mk1 or 15mm fisheye would be useful.
Any recommendations for a similar lens, good for architecture without a lot of distortion? Aperture isn't a driving factor for me, since I'm on a tripod the majority of the time.