I have owned a 2004 Ko'Aloha Crown Bridge tenor; currently own a 2017 KTM-00; and had the opportunity to play and compare a 2019(?) KTM-00.
The unibrace has indeed evolved. The 2004 was fairly thick and positioned close to the sound hole. The 2017 was thinner, the hole was bigger, and it was moved a bit away from the sound hole. The newest version has several differences regarding the fretboard, sound hole position, and the unibrace was thinned more, and moved again. I can't speak to the other braces, or interior details.
The 2004 was definitely a "boomer". Lots of C low end. Got a bit muddy when pushed. But still sounded good.
My 2017 is less boomy. But has plenty of C Low end. Fun to strum and pick. A wound low-G can overpower the other strings.
I thought the new version had better balanced tone. Cleaner. The lows weren't quite as low and the mids and highs seemed to have better definition. Especially the A string. You can push it and the note separation seems better.