Are you sure your axle is currently above the springs? Because by 2004, most fivers were already spring over axle.
Whether it is or not, you still have to lift the trailer for safe clearance over the bed. It is just a matter of how that will be done.
There aren't any negatives to doing that to be concerned with. Your center of gravity will be higher. You might need an extra step at your entrance door, either a new box step set, or else a step stool on the ground. Going higher will add stress to the spring hangers. If it is done right that won't be a problem. You will be pretty much recreating what all newer trailers have.
The key will be finding a shop that you trust to know how to do it right.