Thanks
Simcoug, I'm looking forward to using it too.
Glad I could provided some ideas
Willy. Curious to learn what is and what is not possible!
Smeel, first of all thanks you for the kind words! Much appreciated!

I'm using the coast controller to fill spaces where I've want forest that the Inland controller doesn't fill.
Hehe, what you've done is almost the same as I did, i.e. using controllers one after another to fill in blank spots. I went Inland -> River -> Coast, in addition to some tweaks in between each session, and I was very pleased with the results. For instance;
The careful observer might notice Girafe's Larches, which are frigging awesome! And alright, I'll admit I just wanted to show of a bit! The variety which comes from using all tree controllers after another hasn't seized to amaze me and in fact gave me the idea to make a new controller 'simply' by superimposing the current controllers onto each other, in order to create a new, super varied controller!
(please note the idea still solely exists in my mind so don't get your hopes up for a release any time soon). Now, onto the question.
This made me thinking about the possibility to have more controllers for specific purposes. I have no idea if this is possible, but would it for example be possible to create a controller that is more conifer heavy, be compatible with your other controllers and would fill the map the same way the coast controller do?
Why yes, that's certainly possible. The easiest would be to take the existing fir & conifers brushes and play around with their Preference Table. This is the basic mechanism which determines where flora is planted, so you could make them appear wherever you'd like. However, as simple as it sounds, getting it right (i.e. going back-and-forth in various tiles to see how it looks) would still take quite some time, which I don't have much atm. Besides, there's other stuff I'd like to spend it on instead.

That said, it's entirely feasible to create another tree controller simply by rearranging flora from mine. If you or anyone else reading along is genuinely interested in doing so, you can send me a PM and I'll happily provide you with the single brushes to play around with and help understanding the basics, if necessary.