Couple of things I can see. If the layout is up against a wall, be careful with access. I built a U shaped layout and I kept the width like 36" or so, and reach in some places is tough (I tried to always have reach to every point on the layout, but there are places where it is difficult, like trying to solder wire to the rails).
With all those switches, be really careful when wiring them, it is really easy when doing so many to kind of lose track of what you are doing (as I well know) Besides labelling the wires from the switch to the controller (I don't know if you plan on using a control panel or fascia mounting them to be near the turnouts or if you plan on using the AIU control of the switch machines) it is very easy to lose track of things (my layout is like 9x14, but I have roughly a dozen switches).
Someone mentioned stalling on the o54/072 switches. There is a way to wire that if you run into problems with that, using relays to avoid that (I am using dz1000 switch machines, I bought the relays to do this with my ross #6 crossovers, but didn't wire them in unless I find I need them).
You should be able to run three trains, since you have passing siding capability with the 2 mains, so that should be good.
You have a lot of sidings that should make for some fun switching fun, or as staging fortrains if that is your desire.
One thing to think about this design is what you want out of the layout. If you are into running multiple trains and having the visual look of cars sitting on sidings , this layout as designed is great. But if you also envision having a layout with a scenic plan, having a lot of tracks can work against that. I probably have much more track on my plan than I should have, for sure, but if I wanted to have a dual track mainline (I love trains passing each other going the other way kind of thing) and the kind of layout where I can have cars staged on sidings, engine sitting and waiting,etc, it meant having more track density and thus I won't have as much scenery options as if I used less track and had more space for scenery.
It isn't this design is wrong, it is just since you are in the design stage thinking about the vision for the layout, is it to run trains, or do you see a high rail scenicked layout you see in OGRR magazine or MR? Obviously as I am already figuring out what I wanted originally and what I was able to build don't fully match (on paper, I thought I had a small dock scene possible, given the reality of the space I had I don't think it is going to work (at least as originally envisioned, might be able to model the approach to a small car float and leave it to the imagination. It is why people modify layouts or redo them, that is part of the fun of the hobby, and thus if you build the layout and find it doesn't fit your vision, or the vision changes, you have reset capability
I agree with others, if you want to run conventional engines, either your own or if a friend visits, you may want to have the capability to run conventional. There are a variety of ways to achieve this with your layout. One way is to block wire it for standard conventional wiring, which if you have a transformer you can control them via 'the handle'. You also can use a Lionel powermaster that allows the Legacy base to vary track power to run conventional engines. If you have/get a lionel ZW-L transformer, the legacy base can vary the output on them, bypassing the need for powermasters.
Another question, not with the plan, has to do with control. Do you plan on running only Lionel command equipment (TMCC/Legacy/Lionchief)? The reason I ask is that if you have any possible thoughts of running MTH equipment with DCS, you may want in your wiring scheme to take that into consideration, even as a future option. DCS because it uses the center rail to send the signal, has unique considerations. The big one (to me) is having 'power districts' (basically electrically isolated segments, similar to block wiring), because there can only be one dcs signal input per segment. Having one dcs signal on a layout your size likely wouldn't work, it is very different than TMCC/Legacy in that regards.Not a hard thing to do when laying track, just using insulating pins or cutting a gap in the middle rail and having power feed to all the segments (one per).DCS also has a bit easier conventional control, the WIU has variable outputs that besides putting out the dcs signal, also can vary the power, to operate conventionally.
Congrats on getting to this point! And if it ever gets you frustrated about how slow it seems to be going, you can always use me as an example and say "no matter how slow it is going, that guy is slower than a snail struggling through 90 weight gear oil at the North Pole in January"