for sure LogicPro is still based on internal "objects", which are represented in the environment, such as channel strip objects, etc. And that underlying engine has not been rebuilt from scratch, Apple came in and put more of a WYSIWYG gui wrapper around it, making it incredibly easier for the average user. Before that, Logic was a bit of a turn off for many people because you had to understand about stringing objects together before you could record a single note of music. With Apple's GUI, they made more like typical DAW's, just add a track, select it and start playing your midi keyboard... but under the covers, LogicPro is still stringing together objects in the environment to accomplish all that using the same underlying object engine.
But anyway the environment is mainly about how midi is routed. The channel strip objects do handle audio obviously, but all the environment does is bring those channel strips into existence. Audio channels get their audio input from somewhere else outside the environment...and send their audio someplace outside the environment..the environment doesn't have that much to do with it. In the environment though, they added all the midi stuff, transformers and so forth..which became kind of a cool thing that other DAW's didn't and don't have. For that reason, its still around and I don't personally think it will go away. (though it is interesting that the environment did not make it into MainStage. MainStage instead includes a set of typical filters that satisfy most people...without the extreme flexibility of LogicPro's environment. It quite possibly is still using the same environment underpinnings though....just no actual environment GUI provided in MainStage).
But anyway, midi was an 8 bit protocol for the most part with with tricky things at times about sending multiple bytes as separate "midi messages" that can be reconstructed into larger data values, but each midi message was 8 bits essentially, and in programming back then it was common to keep integer sizes as small as possible. if you only needed 8 bits, then you would program the thing to use 8 bits, to conserve memory and reduce any processing to absolute minimal. So its not at all surprising to me that Emagic would have "optimized" the environment in many ways to pass 8 bit numbers around and do fancy bit math on it to extract various things out of the 8 bit bytes, etc. That would have been considered an "optimization" back in the day.
so anyway, my opinion, the guts of the environment in terms of how midi is routed around..is the part that is probably stuck a bit in 8 bit. And quite possibly it was even written in assembly rather then using a compiled language like C/C++ honestly. There is all kinds of weirdness that we don't know about. 8 bit midi messages are already packing just about all the info they can pack per event. So then, LogicPro has added things like midi port and articulationID as additional attributes of events... and they do somehow make it all the way to the plugins in the instrument channel...but...we can't see those attributes at all in the environment...all the transformers and everything are completely blind to it. So..obviously there is something inside LogicPro that represents midi events with more then 8 bits...but the environment still has old 8bit cob webs all over the place....and basically it does not surprise me at all if occasionally something will cause it to throw fits...and it would probably be very difficult for a current engineer at Apple to go figure it out...and they are probably, and rightly, scared of breaking it! So they don't want to muck with it too much unless they really have to.