This was not called execution. it was called promotion.
Liking the idea so far. As long as super abilities that wipe out fleets etc are expensive enough. Finishing techs should also be an expensive endeavour as some techs are game changing, such as ship sizes.
Some of these could make for good story telling, such as a commander ramming his ship loaded with nukes into the enemy. "Crunch Time" made me chuckle a bit. I believe some programmers shuddered though!