you are certainly not the first to ask this, and i shall give the answer i gave the last couple of times in the least sexist way i can, so i dont end up insulting people
the reason there is little female heros is as you say, there are few major female character in the books. now whether this was the era it was written in, personal choice ,chance etc….i dont think it matters….the point is though, ffg are purposely working with the book's characters which, i think everyone can agree, is a good thing….we are here afterall because of tolkien's creation
now someone could say 'just make some up' or make the lesser known female characters heros…and that is perfectly fine, but i think it just comes down to the designers concentrating on the core characters
you would probably think that there would be a good few females to make heros…but i have read the trilogy more times than i can remember, and there really isnt that many.
i really have no problem if ffg decide to create some female heros such as beravor, i mean she is a great creation, and is in line with tokien lore, but i dont see them doing it just for that reason…which brings me onto your question of plans for others….the answer is no, but there seems to be at least a couple of women spoiled in the upcoming gondor packs.
i wouldnt fear though…we still have a lobelia sackville baggins to come..and she is worth at least 3 characters
PS. i'd just like to point out i dont speak for the design team, they may or may not have the same ideas as i posted here (just thought id post that as its a sesitive subject and i like being respected on this forum )