I actually think the 1 minute duration for your slow is the best part of your houserule.
It fixes a lot of people's concerns about no impact at 0 hp. You have ensured that going to 0 hp has a lasting legacy for the fight, even if the person is healed. However, the impact is not as long lasting as the common exhaustion variant people like. I feel like your houserule is more in line with standard dnd while still fixing some of the issues with 0 hp and death saves.
I think pulling back from that removes some of the teeth. Going to 0 hp should be nasty business, and I think your rule mirrors that very well. I might actually try it in my next game.
It fixes a lot of people's concerns about no impact at 0 hp. You have ensured that going to 0 hp has a lasting legacy for the fight, even if the person is healed. However, the impact is not as long lasting as the common exhaustion variant people like. I feel like your houserule is more in line with standard dnd while still fixing some of the issues with 0 hp and death saves.
I think pulling back from that removes some of the teeth. Going to 0 hp should be nasty business, and I think your rule mirrors that very well. I might actually try it in my next game.