Springs and axles are a general concern on any towable RV with either Lippert or Dexter undercarriages. This is because the springs are made in China with Chinese steel. In addition, manufacturers don't always take into consideration the side-to-side differences in weight (i.e. one side being 500 - 800 lbs. heavier than the other because of appliances, etc.). You're seeing more issues with the Reflection series than with the Imagine trailers because the Reflections are just heavier units. The fact is that solid axles and leaf springs are 150 year old technology... at least. Those who have had issues or have been preemptive about it have swapped out the springs for ones made in the U.S. with U.S. steel taking into consideration weight differences between the sides. They also often replace/upgrade other suspension components such as shackles and install wet bolts and the like.
Bottom line, I wouldn't let these concerns stop me from buying an Imagine if there's one that is a good floor plan for you and fits your needs. GD's customer service is excellent (from personal experience). We've been full-time in our Reflection for over four years and 40K miles and are happy with it. We did replace the old-tech suspension with the MOR/ryde independent suspension and disk brakes - not a necessity for those not full-timing or putting on a lot of miles.
Rob