Seems like a change that would make things worse not better. If I have 100 health less than the enemy acu when I die why should I lose when they should die to the explosion? You can just play non-assassination custom games if you dont like drawing games when both ACUs die at the same time.
As already mentioned by pearl the potential for a draw also increases the strategic options by allowing you to try and push for a draw if you think you’re behind
As for lower ranked players gaining rating, the rating system will deal with this automatically-theyll end up losing more of the games where they cant force a draw if their rank is ‘inflated’ from forcing draws, while higher ranked players should be capable of avoiding a draw against a lower ranked player.
The only issue this might help is the bug that gives a win for a draw. Fundamental changes to game mechanics just to adjust a minor flaw with rating (that due to how the rating system works is unlikely to have a notable impact over time) doesnt seem like a good idea.