Regarding brushless motors... Marklin tried them in their HO product line about ten years ago. Google 'Softdrive Sinus' or something like that. They met with mixed reviews. I think Marklin ended up dropping them and going back to brush (servomotors) with feedback speed control. As an aside, Marklin cataloged locos with back-EMF speed control in 1995, well before Lionel or MTH. So maybe their pioneering use of brushless motors is a harbinger of things to come.
I'm not really sure what the issues with brushless motors were, or why they weren't better accepted by the Marklin crowd. I know brushless and battery power are now competing with small gasoline engines for use in R/C airplanes!