No one complains about a backwards incompatibility if you take a class that started off Sealed and make it unSealed. Few (if any) people tend to complain if you make something that used to error now work.
People tend to be rather upset, with good reason, if you take a class that started off unSealed and make it Sealed.
My suspicion is that no one offered a compelling reason to make the table class unSealed, so it defaulted to Sealed. I recommend that you contact Technical Support and ask them to submit an enhancement in the enhancement database with the features with which you would like to imbue the table class and your use case (how you would use those features and/or why you want to use those features.) It's possible that could be a compelling reason to unseal the table class, or it might be compelling enough to warrant inclusion in the table class itself.
