Ok, I may have exaggerated to emphasise my point, but you cannot say that if you took away the Praetorians, the annona ration and ludi days Rome under the principate would have functioned with little unrest. It is true that since Republican times Rome's law courts were unsurpassed by any other nation, but you said yourself that the urban poor of Rome faced great social injustice, and in my view a fully functioning judicial system was not enough to quell the discontent caused it. As mentioned earlier emperors had to resort to 'bread and circuses'in order to pull the wool over the eyes of the poor.
It wasn't just in Ancient Rome that alternate methods were used to distract people from 'social injustice'. I mean look at Britain during the 1930s depression: though the country had a near fully developed legal system unemployment had skyrocketed, the majority working class poor were actually living below the poverty line and according to George Orwell's The Road to Wiggin Pier it seemed to be a time for social 'revolution, not patching'. Yet despite this, Britain never really experienced social unrest on a large scale. What I would put down to is the fact that various industries were developing during this period, and as a result of this cinema tickets, basic food (e.g. fish and chips) and (due to the opening of Marks and Spencer's chain stores etc.) basic cloths were all affordable. So it could be argued that during this period, the 'bread and circuses' approach was more effective way of keeping the urban poor contented than the concept of 'justice'.
I know it is wrong to draw parallels with 1930s Britain and Rome under the principate--the cultures are nearly 2000 years apart--but what I was illustrating was the fact that distraction from social injustice occurred in modern, judicially developed societies, so why shouldn't it have occurred in Ancient Rome?
Sorry about that, all the dates on the original essay were from memory. I also noticed that I said Titus' reign started in 78 AD not 79 AD.
However, the dates regarding the annona ration from 58 BC to the time of the principate are few and far between: it seems that it wasn't until 22 BC, when Augustus provided corn as a means of famine relief, that the annona ration became a set right for ever male freeborn Roman.