What is the future of the Batman: Arkham Franchise?

WARNING: MINOR SPOILERS FOR BATMAN ARKHAM: KNIGHT ARE BELOW!!!

 After playing the first three Batman games (Arkham Asylum: GOTY, Arkham City: GOTY, and Arkham Origins) in 2010, 2012, and AO's release of 2013, respectively, I was very much looking forward to the release of the franchise's fourth installment: Arkham Knight. I got the chance to play it at a mate's house for about 6-7 hours, and I got through the main story, and most of the side missions, and I was looking at the ending to the story (and I know that there are two separate endings, as I have seen both endings in front of my face), and it was a very closed ending. It was the perfect way to the end the franchise, right there and then.

 But does that mean that the Batman: Arkham franchise is over? Maybe not. I was talking to my mate (who owns the game), and we agreed that there might be three options with the future of the franchise:

1. Do another prequel to Arkham Asylum. Whilst this might be a stupid idea to some, and that there has already been a prequel to the series (Origins, released in 2013), there is a significant time difference between Origins and Asylum. They could fit two more games in there and make a trilogy. I would, however, expect it to be WB Montreal who would develop the games, and judging by what some people have been telling me, they aren't big fans of WB Montreal, because they didn't enjoy Origins. However, I personally enjoyed the game, and I see no better option to continue the Batman: Arkham franchise than to do another prequel.

2. Do a completely separate game that is inside the Arkhamverse. Why not make a game based on the Suicide Squad, or the 8 assassins in Arkham Origins? Whilst this probably will not happen, it is quite a possibility, as some fans would want the Arkhamverse to expand a lot further than just 4 games which revolve around Batman and friends.

3. End the franchise. This is the most likely of the three options. Whilst the games have been exciting to play, all great things must come to an end (like Metroid, Crash Bandicoot among others). The ending of the game was enough to say "Thanks for playing the Arkham games over many years. We hope you enjoyed it, but enough's enough. This is it. This is the end."

 What do you think is going to happen with the Batman: Arkham franchise? Could there be another prequel? Could there be another game set within the Arkhamverse? Or is Arkham Knight really the end of the Batman: Arkham franchise for good? Give us your thoughts below