What I would like to see in new troops/hero: make similar to xbow or inferno tower
I think the best part about planning a city at TH9 and 10 is that we get more unique bases due to the ability to change how an xbow or inferno tower is oriented. This gives the defending city the ability to customize the orientation to play to the strengths of the layout and what the defender thinks is most likely to attack. This causes strengths in one area, but results in a weakness in another.
Along that line of thought, I began to think after watching the Nordic Championship that it would be nice to have more variety in our troops or heroes based on what the player thinks works best. Obviously, we do this with each army we build, but it would be nice to add to the complexity of established attack patterns by having a troop that attacks in a different way based on something we choose prior to entering the battle. Having something like the mulitarget vs single target mode of inferno towers or air&ground vs just ground with xbows adds that layer of complexity.
While I think this is a broad topic, I wanted to add a bit of conjecture on what I think works best. Between troops and heroes, I think a hero with different settings adds more. For starters, I think a hero with a variable setting adds to the influence of the hero and his/her ability to augment a fight. A barbarian raid is different with a king tanking, and that fight changes dramatically when the king rages. Likewise, a queen behind a b-arch attack is very different than just a b-arch attack, cloak or no cloak. Likewise, on defense, this could have consequences for the defender, just as the setting for the xbow or inferno has a consequence. These little changes make for big planning shifts, often in a small amount of time.
I understand there are no plans to release a new hero or troop immediately. In expressing this idea, I am just reaching for a ways to make well-established and enjoyable mechanics a little more personalized.