How could it be better? Brightscript is a proprietary language that serves nothing but a low power STB.
On hackers news a technology focused platform where custom weird languages thrive. You're complaining about a company who the original developer made their own language.
Isn't this exactly how all of the other languages where created?
Personally I'd rather it not exist. Roku would be more pleasant to develop on had they chosen a more popular, existing language as the basis (e.g. Python). Then the task of developing for the platform ~mostly reduces from "learn a new language and a new framework" to just the latter.
I suppose it hasn't inhibited their success, of course.