> if I think if we were to take a look around at heavy web frameworks today, we would see a very similar approach of "let the developer decide" when dealing with Model security and serialization of fields
What everyone else is doing isn't a great justification--if decisions in Rails were based on what everyone else was doing, it would have been written in Java. In terms of Rails opinions, sensible defaults would be one that would suggest this should be rethought. In terms of rewrite-work, the Rails team didn't shy away from that with Rails 3, but I think the cross site scripting protection was worth the work. And even if the default is changed, nothing stops it from being a single line of code to turn it off.
What everyone else is doing isn't a great justification--if decisions in Rails were based on what everyone else was doing, it would have been written in Java. In terms of Rails opinions, sensible defaults would be one that would suggest this should be rethought. In terms of rewrite-work, the Rails team didn't shy away from that with Rails 3, but I think the cross site scripting protection was worth the work. And even if the default is changed, nothing stops it from being a single line of code to turn it off.