Reasons

Bob Brines, Jim Salk, and Dennis Murphy to name a few have all used my software (Paul Kittinger did the actual TL design work for the later two) to design the TL portions of their speakers. Bob Brines was a very early supporter of the software and is a very talented designer, his understanding of TLs is excellent.

I think there is some adjustment potential with a TL design. Adding internal obstructions and/or a constriction at the open end can always be used to change the tuning frequency and response. Also changes to the stuffing density and location is another tweak that can be used to change the TL's response.  

Are you saying we could build a TL speaker enclosure, to accepted design, ....and then play around with the exit size to see if it enhances the sound?  (along with changing the stuffing and its placement)  This sounds like 'fun' to me! 

Yes, that is what I am saying. I am talking about small changes to the tuning and sound, not transforming a poor performing speaker design to a world beater. The trade-offs may have improvements in one area but degradation in another. No magic, no miracles.