Original abilities would be rehashing visual effects. We don't have the ability to create new effects and animations. Making abilities has gotten easier over the years, but there's still plenty of variables in the client we don't fully understand.
More spec trees is not going to happen. Each class will be stuck with three trees.
More renown points will not happen. Stat creep ends at RR80 with full sov gear. Everything else needs to fit under that ceiling. Renown tactics are planned for implementation in the future, but the specifics haven't been fully worked out yet.