The reasons ROTE wasn't used are:
ROTE does not support Unicode, does only cover like 1% of required escape-sequences, has not seen any update for like 5 years, does not support 256colors, does not support XKB input...
Same applies for VTERM which is based on it. And from my experience I can tell you that if Unicode support isn't planned right from the beginning, I wouldn't base my work on this.