Ramming ships and shield wall ships would kick ass, but I have no idea if the current modding system allows you to modify the AI to actually match these ideas. If you could set the AI up to work like this, it'd be plenty of fun all by itself.
Shield ball sounds like cannon fodder, which could work but maybe it could do with some slight support weapons - a few vulcan cannons or the like on some tier 1 ballistic mounts could help make it more useful.
Ships with weapons outside of the shields sound a bit useless to me - I would personally stick with properly shielded ships in that case, unless the odd new ships would be really powerful.