My wife's vegetarian so I've seen a lot of special meals in F and CW. What she does these days is book the Vegan meal as a backup and, if there's something on the F menu that looks suitable, she'll often have that instead.

The BA straight vegetarian option is often bloody horrible, even in F. It's usually pasta, often in an uninspired and bland sauce. If the pasta option is veggie in the regular bistro menu (and it often is), it's usually miles better. The F cabin staff have often been really embarrassed by what they've had to provide as a veggie special meal (they get no notes on it either, so it's always a mystery meal). The vegan option has been a lot more edible.

If you have a chat with the staff when the menus get handed out, you should be able to negotiate the best of the options on board - they want you to be happy and have almost always been really flexible and open about what's possible.

We were told by the cabin staff on the last trip that BA were experimenting with different special meals catering on the New York route. Hopefully it'll pick up a bit.