a little better than Watch_dogs because we are closer to holidays

Short term success :) as most 3rd party games.

I think it will depend on the quality of the expansions and how well they are implemented by bungie over the long haul.

Probably something like that. Some people might consider that dying down compared to its initial numbers.

I think there will probably be enough of a fanbase established to make Destiny into a new franchise, as per Activision's 10 year plan for the game, which with proper updates and responses to user feedback, is entirely possible.

Not saying that it will be one of those titles that everyone who owns a non-Nintendo console will buy the way MK and SB are games that virtually every Nintendo console owning consumer buys, but it should do well enough and keep enough players on Destiny servers to keep the franchise going and growing.

Titanfall's biggest problem is that it was touted as a next-gen title (even though like Destiny, it showed up on the XB360), but didn't show up on the #1 next gen platform due to lack of foresight. They figured Xbox would be the 8th gen platform of choice and they made a mistake, hence the general lack of interest for the TF for the overall gaming market. Plus it may just be that gamers didn't think it was as good as the hype, regardless of whether it was available on the PS4/PS3.

I don't think it will have as long legs as MK8 but it will probably have longer legs than Titanfall. Destiny has the advantage of being on more platforms afterall. The only thing I can see working against it is its massive initial sales. It looks like word of mouth might be negative, at least according to the internet, so it's legs will be a bit shorter. I'm still having a blast with it though!

Probably very long legs it will be the new casual mass market game like CoD and FIFA

Bigger than Titanfall, and will last slightly longer for PS4 because it is the only way to get a white PS4 before it is unbundled for the holidays

Smaller than Mario Kart 8 because it's a new IP obviously!

It depends how severe the lack of content and how limited the mission design really is.

aka the quality will be the deciding factor