I think a lot of those suggestions are pretty good Jetplane, however I agree with Marked in the fact that we probably shouldn't change particular blocks to suit particular builds. If we want to change something it should be for aesthetic enhancement of the existing characteristics, or, in the case of things like end rods and such, be changed to the most general Tamriel-related thing possible.
Solaris, the problem with changing banners is, we already did that. I don't think the experiment worked, as I hardly see the changed icons I made getting used. Currently there's a moon-and-star icon and a Mages Guild icon in the banners. So, keeping with the above, we should probably change the banner graphics to stuff that's more practical than any particular logo. Perhaps geometric shapes or even back to the defaults. I'm really not sure.
The birch I think would look alright if it was a less... extreme yellow. We have a lot of different shades to choose from
, so something in between pink-peach and yellow should be attainable.
Oh! There's also the consideration of changing the leaf and grass characteristics in the Mushroom Island biome. I'd really like it if we could get the grass there to be teal for use in Alinor.