1. At the current moment, when an asteroid or moon strikes a planet, the impact shock/blast wave will begin to expand outward, but depending on the size, the wave will fade out halfway across the planet, but other times, it will reach the other side. I feel that it would really be cool that, depending on the size of the asteroid and force of the impact, it would create a blast wave powerful enough to cover the planet or just the small impacted area. Think of the impact scenes in Armageddon.
https://www.youtube.com/watch?v=N3nyn_yZQ98 https://www.youtube.com/watch?v=GbaQD6eF_qc2. I think it would be cool for an asteroid that's 6 miles or larger to slam into Earth and have the impact wave completely incinerate the planet's surface. The wave would wash over continents and oceans, engulfing them, again, like the scene from Armageddon.
3. Seeing as how cities and other places are planned to be implemented, how possible would it be to implement things like visual tsunamis and fire storms? I think it would be cool to watch cities get engulfed by tsunamis or from the blast wave. Take this for example.
https://www.youtube.com/watch?v=VNtsVP42bOE4. How much detail will go onto the planet's surface? Cities are coming, but what about things like highways and forests? This could be useful in re-enacting certain events, like the Tunguska explosion in 1908.
Just a few things I thought of.