No it's not just you, but it's not a recent development either. It's always been terrible, to the point where you can often miss where the ball is completely. The same applies to all TV Anywhere streaming channels.
Sky Go on the other hand, serves up HD streams which look better than my TiVo does on the big screen.
I have written to BT Sport about this (and the fact that the whole TV Anywhere platform falls over to some degree or other every time they have a match on) & am awaiting their reply.