Chef - I discovered the same thing with our 210UDS.
Haven't decided to replace the wimpy jacks yet but it's on my eventually do list. While I was looking at the upgraded jacks I came to the same conclusion, fronts easy. Rear? I like the idea of larger plates welded to provide solid support.
Not sure why CruiserRV went with such inadequate/poorly suited jacks.
I did notice that any larger/heavier replacement scissor jacks have a larger profile and hang down more. This could pose a problem with steep driveways or sites where you need every inch of the camper spot and back in deep - I've sometimes been able to back the rear "over" whatever marks the back of the camper parking slot (R/R tie, log, etc.)
Just something to consider. . .
2012 FunFinder X 210UDS
4-68 watt flexible panels; 1-215 glass panel/4 Battle Born LiFePO4 Deep Cycle Batteries
2014 Ford F350 6.7 Liter PowerStroke V-8 Diesel longbed, SRW