As we already know, Trajan brought the Roman Empire into the so called "greatest extent". Now let's say that there were some rebellions and barbarian incursions in Britain, North Africa, as well as along the Rhine and Danube during Trajan's reign, keeping him busy enough into not going for the conquests like we know it.
What I want to ask was, did Trajan's conquests have some macrohistorical importance? If it never happened, when would be the Rome's greatest extent?