Critique a Homebrew Rule Before You Add It to Your Game

Adding a house rule to fix something feels obvious until session three, when the fix has created two new problems. Rules interact in ways that are easy to miss when you are focused on the one thing you want to change. This critiques your proposed change before it goes to the table, with a focus on second-order effects and whether there is a cleaner solution.

I want to add a homebrew rule to a game and I want a critique of it before I introduce it to the table.

The game system or game I am modifying: [describe]
The rule I want to add or change: [describe the rule as clearly as possible]
The problem I am trying to solve with it: [describe what is not working and why you think this rule will help]

Tell me: whether the rule actually solves the problem I described, what second-order effects it might have on gameplay I have not considered, whether it is likely to create new problems or unbalance anything, and whether there is a simpler or better-known solution to the same problem.