Right now the stat threshold feature is a minimum – many people want to make sure to reach thresholds of stats no matter what. We don’t currently have a mechanism for enforcing maximums, but we can put it on the list of things to look into for the future. In general we try to set up the optimizer such that it is not really necessary.
Defense is still a pretty good stat even above the crit immunity threshold… one shouldn’t work too hard to avoid it (ha!). But if you have a test case where you think the optimizer is too heavily favoring avoidance over stamina, I can take a closer look. In general our goal was to set the optimizer to a good balance where it will choose stamina on most gems, but not to such an extent that it would sacrifice “free” stats from socket bonuses. If that ends up going a bit over 540 defense that’s not a big deal – having more total defensive stats should be a net win as long as you aren’t sacrificing too much stamina to do so.
I’d like to try adjusting that balance if necessary first before adding an entirely new customization feature – ideally setting a custom maximum on defense shouldn’t be something a user needs to worry about.
If you haven’t done one before, the best way to provide a test case is with a snapshot of your setup, instructions on how to do that in this post: