they are called commander cause they relay orders, keep your units at the front you want them at rather then a specific repair station's way-point marker. they also make your units focus fire on one hostile at a time with out you micro managing a group that breaks up & go... god knows where, as they retreat with damage.
if your keeping groups (possibly specialised in some way) together, and using strategies & tactics rather then brain-dead swarming, commanders are much more useful then the standard group commands. an ability i feel almost lost without in C&C or total annihilation, although in wz2100 more emphasis is placed on unit survivability.
if anything, giving them a wide area guard, that allowed some level of pursuit. but calculate survivability threshold probabilities based on the area of the map its in, which then cause it to return to where it was if the risk is getting too high.
in the campaigns, the commanders i build in cam1 (and alot of my ranked units that i assign), are the same ones killing nexus at the end.
meaning they are noticeably stronger then unranked units. which is useful
thats allot of unit exp, let alone resources down the drain.
as for making the game too easy, it already is

especially in the campaign >:(
collective 1 is one of the harder ones, and iv completed it in 12 mins., on hard, with no unit losses