Welcome to the site.
We bought a 2012 Crusader 290RLT new in June of 2012. After I read your post, I thought 1st how do you walk on the slide with the table other than to set down at the table. I went out to the RV and moved the chairs and walked in by the table. I did not notice much flex or movement in the slide. I put the chairs back and sat down in the outside chair. Again I did not notice what I might consider unusual movement. I hope that this isn't a problem with your RV slide. One of the members on this site is RV Guy. He works at PrimeTime so he might be able to answer your concern.
We have traveled about 12000 miles in the last 16 months. WE have had very few problems and absolutely love the Crusader 290RLT floor plan.
Good Luck with your Crusader.