I just looked up the specs. of your 5er, I like it
Flagstaff Classic Super Lite Fifth Wheels / Travel Trailers by Forest River RV
I'm a little surprised they get away with 4,000 # axles, you're already at over 90%, better to keep a close eye on axles, bearings and especially the tires.
Leveling the load (trailer) would definitely help with distributing the weight better between both axles. Looking at your pic., I don't see how you could lower the front end without risking some nasty mishap sometime down the road. If I had to do it, I would get the lift kit and plan for an axle upgrade down the road. I know it's expensive, but you'll be a lot happier in the long run.
Edit: Kudos for paying attention, some folks just hook up and go and then complain when something goes wrong.