archmages are very good in the beginning their no range penalty is excellent for hitting the archers in beginning(and their shield is good for a tank)
and for a better unit input
i would suggest
Priest>inqi ASAP
horseman or griffins>royal snakes
don't keep 2 melee units in the beginning
with some proper unit control u can fed off most beginning units with 4 ranged and 1 tank
for a steamrolling beginning
i would suggest this input
INQI(must have)
horseman/royal snake(any of those whichever is avaible)
alchemist(great unit (killing thorns and poisiong the other)
archmages (see above)
and the level 4 unit u get at arlnia after dragon fang quest(unless it's a undead commander)
i mostly get shamans there and they are just GREAT to say the least their abilities are just POWER
when u get lucky u might get demons and well they don't need any further introduction ^^