Assuming that it is still allows changes - just with a nominal fee - this will really cause some hurt to business travelers because my guess is many corporates will accept the unbundled business class discount* (afterall, it's still a J seat) whereas most corporates have been hesitant to do the same for Y out of fear of revolt from travelers stuck in terrible middle seats or not being upgrade eligible to C+/F.

* By discount, I mean the old J pricing, with the new "bundled" pricing being J + a fee, just like how it worked with Basic Economy after a couple of years.