What's your opinion on the slack in this 318 timing chain?

Wise decision in my humble opinion. I still believe what you already have is better than the junk that's forced on us. Even names such as moog, BF Goodrich, timkin, etc etc that were once associated with quality are now compromised and produced off shore in the name of profit. If your timing chain had 100,000 miles on it ok yeah change it out but not with minimal slack and 10,000 miles. Again just my thoughts, others may disagree.
I have a belief that they will continue to produce junk parts until people stop repairing old vehicles...as long as people pay they will still sell us junk till we give up.