From "Help warcry"

A warcry should not be chosen lightly, for those who shout uninspiring or
inappropriate words have been known to lose the beneficial effects that
the warcry might bring. Non-sensical warcrys or "just noise" like 'GRAAAAAAGH'
or 'Ah-mu Ah-mu Ah-mu' are likely to fall into this category. Well chosen
warcries that are especially pleasing to the gods have been known to carry
with them enhanced inspiration.

Neither ALL CAPS nor excessive punctuation need be used in a Warcry-- it's
assumed to be shouted, and easier to read if written normally.