You guys are such pessimists!
Keeping mortal commanders alive, or dying trying, is actually one of my favorite things to do in Dominions, and it can be done... not with any certainty, but if it were certain, there'd be no tension nor interest on my part.
Equipment for him would depend on what he's going up against, and thematic considerations. His weaknesses are of course mortal HP and low MR, and currently, pretty low Prot too, and vulnerability to missiles (which you can't do anything about without spells or magic if Champion's Trident takes all your hands). His Def is good enough but Def is one main way to keep mortals alive on the field, so the higher the better. But address the above issues if you can. The most important against AI and easiest to deal with are Prot and missiles. Chainmail of Displacement is good, as is Jade Armor or Boots of Quickness. Stoneskin or barkskin could help, and if you have one of those, then Starshine Skullcap could give enough head protection while increasing MR. Mages assigned to buff him are another option. Be sure to assign some bodyguards on Guard Commander who are fast enough to keep up with him on the battlefield.
PvK