I have not heard the 4349 so I can’t really comment. It is the “cheapest” JBL to get the duel diaphragm compression driver which is a good thing but it is also pretty small at 1.5”. The bass driver has the same motor structure as their top of the line models.
I saw an interview with one of the JBL sales men/engineers and they commented on 4349 being the best “buy” in their line as it sounds a lot like (as in almost the same) as their top model (SCL-1) at a fraction of the price.
based purely on looking at the data I feel like the 4349 is comprised a bit and probably should have had a 2” compression driver to allow for a lower crossover. It would eliminate that dip and help with distortion. In actual music enjoyment with room reflections I am guess you will not hear the dip.
I own the 4367 and I personally have not head a more detailed treble. It is not fake detail from lifted treble either. If anything the speaker errors on the warm side which works for me as I am not too much into audiophile music these days and have just been listing to “real” music from my youth. I guess that is a sign of a good speaker as everything is good and the best stuff is still outstanding. Also don’t over look the adjustable horn levels. It really makes a big difference. 0.5db steps does not seem like much but it changes the speakers over all sound a lot.
I am sure there is better but at what cost and effort. If you like your current JBLs I am sure you will like the higher models. To my ear the higher models are much better.