model size

[Cleaner]

Cleaner, I see that you put shoot-through issues above poly count in general

Yes and there's no problems with this at all.
That 'shoot-through' issue is real pain and unfortunately there is no escape, you have fully close the models and add a back-face to single plane models.
At the end of the day we're talking about merely just a few extra polys so yes anti shoot-through primes.

most of your latest models are rather high poly.
This makes me wonder whether the low-poly-guideline has been changed in any way? Or are there even some engine tweaks going to be revealed with v1.2, which will handle those amounts better?

Policy is still to keep polys as low as you possibly can, the thing is that sometimes you can't.
Only just a few of my latest models have a poly count above the average but I tested these models on the crappiest of my pc (the one that overheats as soon as I move the mouse).