I don't believe that is the case. I know some schools teach BBC BASIC (for Windows), which of course was specifically designed for the purpose: http://www.bb4w.com/
Using '[' to enter the assembler still works in BBC BASIC for Windows, except that of course it accepts IA-32 (x86) instructions rather than the 6502 instructions of the old BBC Micro. The power of being able to mix BASIC and assembler code in the same program is as great as ever.
BBC BASIC for Windows does implement MODE 7 (teletext) and the SOUND statement!