RL uses a SpeedTree derivative that is in need of an update. There have been various ST-related entries in the Feedback Tracker, some dating back almost five years ago.
As it is now, we don't have a good tree system. It doesn't render properly in Iray and it can't be exported to, for example, Omniverse.
The characters you can create look better and better and in comparison the trees look (kind of) sub-par.
Of course we'll probably get the usual answer "It's not in the planning", but it should. The solution doesn't have to be SpeedTree, as long it's something that looks better.