I want one of my characters be more "tank-like", where the focus is more on a defensive build that focuses on survival and less on being an offensive powerhouse.

Ever since "Warrior" gear was changed to have a STR(ength) requirement, I'm having to allocate points that I wanted to put into CON(stitution) into STR instead. Because without STR I can't wear higher level armor.

This seems broken, and I'm not sure what the best solution is (as there are a few ways this can be addressed). I think the one I would prefer to see is that all gear that has a STR requirement instead be changed to "STR *or* CON" requirement instead to accommodate both types of fighter builds. So, a piece of armor that "Strength required: 8" would now instead say "Strength or Constitution required: 8", meaning a character with 8 CON and 6 STR could wear that armor, as could a character with 6 CON and 8 STR.

Or, are you purposely trying to create a situation where characters can't afford to heavily invest in CON for some balance issue you're concerned about?