Unity 5.5.0 on OSX crashing in large scene

Are other people besides me having issues with Unity 5.5.0f3 on complex scenes? I'm trying to figure out if I have a script compatibility issue, a Unity 5.5 platform issue, or an OSX Sierra issue.

I have a large outdoor scene with an open-world build building (no scene load to enter). Under Unity 5.4 on this same machine, performance is actually okay in a standalone build (35+ FPS) and slow but usable (15~25 FPS) playing in the editor, because I am aggressively culling and because my geometry is relatively low-poly for this type of scene. Lighting is all realtime, because baking takes 6.5 hours on this system, and this is a proof-of-concept that I don't have to try to actually publish.

In Unity 5.5.0f3, Unity was crashing at first when I would load this scene. I rebaked occlusion culling, and then it stopped crashing "as much". Unfortunately, I'm finding that Unity eats a lot of CPU just moving around the scene, but when I stop moving the editor camera, the CPU usage quiets quickly.

In game mode, 5.5.0f3 actually seems (anecdotally) a little faster for this scene.

The big problem, though, is that Unity crashes for me after I've had the scene open for a while. Under 5.4.2, I can edit the same scene for hours at a time without a crash. The crash happens even if I never enter play mode. I have a few ExecuteInEditorMode scripts, but if I open a small scene with all of those scripts instantiated on GameObjects, it doesn't crash.

Ironically, I'm about to move from Mac to a dual-boot Windows/Linux system, because I need more GPU power than what Apple is offering in their new machines (and mine is 4 years old and has a failing keyboard, so I have to do *something*). So this problem may go away in a couple of weeks when my new laptop arrives.

All that being said -- and I apologize for the circuitous path -- I'm trying to figure out if I have a problem here that is Unity 5.5 and/or platform issue with Unity 5.5, or if I have some kind of a Unity 5.5 compatibility issue with a script somewhere. Basically, what I'm asking (I think) is, "are other people having this kind of problem in 5.5 on OSX Sierra?"

One possible clue is that I have a number of Substance materials in this scene, and I did find that those issued error messages until I manually reimported each SBAR file, after which they appear to be working fine and do not issue errors.

Is there any way in Unity editor to get the equivalent of the Profiler but from the scene view itself instead of the running game?

Fortunately, I am working with a copy of my project, rather than the original, so I can keep working in 5.4 for now until I get this sorted. Breaking this 13GB project down into pieces to try to eliminate possible causes is going to be exceedingly tedious.

Thanks for any comments or suggestions.

 

Addendum: I know a lot of Unity veterans will say, "Don't aggressively adopt a new major release." I understand and agree with that completely. I'm not "adopting" 5.5 yet, just trying to do some early testing because some of the Unity team at Unite advised me that 5.5 might fix some light baking issues I'm having. But rest assured, I'm not just willy-nilly dumping my projects into 5.5.