This is a bit general, I'll comment on the support needed / I want:
Currently, i have several feeds in Hebrew, but they are displayed most of them time as left to write.
This is OK as long as there are not English letter in the sentences, because then it gets all messed up.
Some of the post are displayed right to left...
Not sure what is the mechanism that decides that, but i would be very very happy if there would be a per-feed option to force all posts from that feed to be RTL.
That should be very easy to implement and would make a HUGE difference for me and many other RTL people.