Previously, building very large templates in Logic around VEP AU3 client plugins required very extensive use of Logic's traditional MIDI instruments, and cabling these instruments in Logic's Environment to the Software Instruments that have VEP AU3 client plugins inserted. In this way it's possible to construct a Logic+VEP template having several thousand instrument tracks.
Now however, if the radical new non-linear (so-called "Live Loops") facilities in Logic 10.5+ are required for use in a VEP template, then the case is altered. Only Logic's Software Instruments and Audio strips are capable of supporting these new Live Loops facilities. Logic's traditional MIDI instruments are not compatible with and cannot directly participate in the functionality of Live Loops.
Because Logic's current design is constrained to a maximum of 1000 software Instruments, then clearly it's not possible to build a VEP template in Logic with more than 1000 instrument tracks, such that the Live Loops facilities are available for use on all tracks. Hybrid templates could of course be built, such that a part of the template would be operable in the "space age" while the other part remains in the "steam age".
I'm prepared to bet that before very long, the tremendous new advantages offered by Logic's non-linear facilities for sketching and writing original scores will become a top priority among serious pro creatives who use Logic. And as a consequence of that preferred usage, it may well happen that two distinctly different stages or phases of computer-aided music-making will eventually emerge:- a concept-exploration and development phase (using a smaller, non-linear template), and a production phase (using a huge linear template).
This first phase would offer limited choice beyond a collection of virtual instruments required just for essential (though complete) orchestration while sketching and writing; the second phase can offer a potentially gigantic choice of virtual instruments for full-scale construction and production of deliverable mock-ups.
It might even turn out that these two phases could each use a different kind of master computer, operating system and DAW (given of course that the first phase would have to include an Apple master running Logic). Moreover, perhaps professional skill sets will eventually become compartmentalised accordingly (as a further evolution of what can already be seen in the working practices of some top pros).
But who knows? One thing though is pretty obvious right now: Logic 10.5+ is very much a game-changer.