I think there could be possibilites of more features. I think they did a slightly sneaky one and devoted all the resources to WP8, even execs at Microsoft admitted that they ran out of time with WP8 as they also wanted to add a notification centre. So I think they ran out of time to update WP7 handsets too. Its either stupid hope but Id expect to see maybe more updates after 7.8 maybe?
I mean if they decided that their going to forget about WP7 owners and give them a crappy update they would have said so. Instead their keeping quiet and working on what can actually be delivered.