The new spawn animation for Baron Nashor is extremley cool and the new behavior is epic. Also I like the way, Nashor affects the rift. As you mentioned, Nashor desroyed parts of the battlefield. I think this sould be showed at the very first spawn of Baron, for example in an giant shockwave, shocking the whole rift.
Could be game-changing, I think you should be able to seem him sometimes... before he actually spawns, you know his spawn animation? Would be cool to see him slither in from a different side of the map, like slither in from bot-lane under the rift, around walls down into holes until he makes his way to his baron spawn, in which he does his little slithering spawn animation, which makes sense.. xD
Baron is like a bug alien thingy right? maybe after he dies an egg sack is dropped and as he gets closer to spawning again the eggs gets progressively bigger and bigger and when he spawns it explodes or something.. this could give a visual estimation on when he will spawn. I did like the slithering around the map idea. Also could help estimate when he,ll spawn. the closer he gets the closer he is to spawning. im just spitballin 
Make him spawn with big fiery explosions and metal music.
