I'm glad you're not so scared to venture off and look to the blue yonder for assets.

I've found some really nice things out there as well and yes, Yandex is a bit confusing even with the translators in place.
I agree that the Speed Trees are a bit heavy size wise. This is something I hope content creators will remedy. I looked into the creation tools myself, but they are well beyond my pensioner's budget, and Windwalkr piped in and said hold off because the version might change. You also need to get the older version as the new one won't work. I'm glad I was informed of that should I decide later when I scrape up some cash. What I would like to see are forest-clumps of a sort. These aren't the full trees with the fancy bark and detailed leaves. We don't need this for the background. What we need are forests with straight simple trunks and a big tree canopy. They would look nice for the background and be realistic as forests tend to have bare bottoms and full tops as the trees drive upwards for light. The other issue I have too is the size of the trees. Where I live, at least, the trees are a lot smaller for the most part. The bigger trees are long gone except around the older homes and estates. The remaining ones became furniture and firewood nearly a century ago, and were most likely cleared away too for the many farms that once dotted New England. Today we have new growth forests and our trees are thinner, smaller, and less densely packed.
Cardboard trees is an excellent analogy. In a sense they are very much like old printed cardstock as the setup is very similar. The image is printed on various bits of cardboard that are crisscrossed in a star pattern. In the architectural world, they use these as well as film positives of tree images to represent foliage. Sound familiar? They look just like the older trees that we have in Trainz. The difference between the cardboard and our older-billboards is our trees will flip around to face the camera. This is why they are sometimes referred to as flip board trees. The problem with them is they don't render well with newer video cards, use up a lot of resources, and worse, don't cast shadows or block light. They will forever look the same whether it's light or dark, raining or snowing. After all, they are pictures of trees pasted on a thin mesh. There are some newer ones, however, that are fairly decent, but they too suffer from the same ills as the older ones will when it comes to the newer simulator (T:ANE) and light blocking and shadow casting will be out. We don't have this capability now, but this seems to be a new feature in the new version which will truly help make things more realistic.
I agree that the replacement process was a bit haphazard to be nice about it. N3V should have been a bit more careful with that as I agree having a multitude of trees being replaced by a single species isn't very well thought out. The problem now is you can't even replace those with the search and replace tool because you'll end up replacing all at once, and this doesn't look good when they are next to each other.
John