I'd really like to see the continuation of the small round buckler shield. We've only seen then used for the skeletons and dwarfs, but I would love to see them used for the Kingdoms line and beyond.
They certainly would go quite well with a smaller bandit faction (i.e. forestmen/wolfpack). Kingdoms is only in its first year so who knows what LEGO has on the drawing board.
I could do without the battle damage slashes overall, but a neutral printed buckler that made it look like wood and steel would be sweet as well as faction printing.
I find it really curious that both the small triangular shield and the kite shield have stayed exactly the same since the day they were introduced, but there have been about four or five different varieties of circular shields over the years.