Do you have a favourite format to play it in?
My favorite format to play in, is probably the same as my favorite format period: Expanded, with Movie not too far behind. Those are also the formats in which the strategy is (probably) strongest.
Fellowship is definitely my least favorite, in general I find it to be boring and limited in terms of variety, by its very nature. There's also not really a good way to set up quickly in Fellowship, nor is there a good way to protect your conditions from being discarded. Towers Standard is somewhat similar, no way to protect conditions, no way to set up quickly. A lot of luck-of-the-draw. I enjoy Open, I just don't get to play it much. RTS I'd play, but I've never been fortunate enough to even get a table going for that.
I find the 20% jumps in win % quite surprising.
Movie and Expanded are a lot stronger than Fellowship or Towers Standard, by the very nature of what strategies are available. Harder to say why TS is doing 20% better than Fellowship, though. It may have more to do with the different meta in TS, than it does with differences in in the actual deck; different site path, different favored minion strategies, etc.
Of course, in TS you do get a site 1 that can pull Gimli, and you also have the cycling advantage of Smeagol, which you don't have in Fellowship. Maybe that accounts for it?