Many trailer makers build to minimum specs and nothing more. Anything above the minimum (whether it be frames, axles sizing, tires, etc) is lost dollars from their pocket. IMO, it's always better to over build instead of meeting minimum specs. Especially if being pulled down the road - where others are at safety risk as well...
When I build trailer frames, I use gussets in every inside corner. Over build, yes. Do I see gussets on may "factory bolt" trailers (including RV and utility trailers)? NO. If you love the trailer but hate its factory frame, take to a welding shop and get them to "improve" factory build - like using gussets. Might be worth it - if you plan to keep your trailer for 8+ years (like I do).
And if getting frame work done, replace its factory brake wiring with much better STAR design wiring using 10 gauge upgrade as well. All of my trailers with brakes have STAR design wiring and its much better than factory as well.