I would think a read function where you give it an address and length would be useful. What else?
primary functions would be
char lcd.readChar(row, col) // reads 1 char
char * lcd.readStr(row, col, len) // reads len chars - should it wrap around end of line?
some ideas:
char lcd.readChar(); // reads form last known (internal) row/col e.g. gotoxy(r,c); x = lcd.readchar()
char lcd.readNext(); // reads a char and moves to next position?
maybe some function to read self made chars / font back into an array?
readback backlight status?
bool lcd.getBackLight()