At the moment, magus PvP is a real struggle. At around 1500 rank magus level is introduced to some serious critical. Although most of these can be prevented with conviction, it is nearly impossible to defend against critical. I think they should add new "commander" gear but instead add a higher rank requirement and add critical block to it. This will really help out pvp for people below level 50.
Even though Magus has some big problems with critical. The levels that Magus warlord will face will not be higher than lvl 70. And trust me it's a struggle to do critical at those levels. What you can do so far is cary some Convictions. There is nothing else you can do. Nicholas Star