The use of + rather than space to concatenate strings is a minor syntactical point, which shouldn't cause any issue except in the case you describe, where you are converting a print into a call. This probably doesn't warrant a change to the language. The requirement to explicitly convert to a string is handled different in different languages. For example, in Java an object is automatically converted to a string when necessary, while in Javascript and C++ an explicit conversion is required, like in Brightscript. I'm not aware of any plans to implement automatic string conversion in Brightscript. It might be reasonable to add an ifBoolean.ToStr() method, although this can easily be implemented as a simple one-line Brightscript function.
function BooleanToStr(b as Boolean) as String
if b then return "true" else return "false"
end function
--Mark