Several different points are relevant:
The earliest evidence for predation known from the fossil record is a hole
in Cloudinia, in the late Precambrian, around 540 million years before the
oldest known hominids. Healed injury (demonstrating attack on live prey
rather than scavenging) is known from the Paleozoic. Venom-injecting fangs
are known from the Triassic.
The ability to change is a good feature for life in the face of a
fluctuating environment.
Satan was fallen before humans, and could have afflicted creation prior to
our fall. This idea is present in C. S. Lewis' science fiction trilogy
(Out of the Silent Planet, Perelandra, That Hideous Strength) and Tolkein's
Silmarilien.
The moral value of animal death is not clear from the Bible. At least
Augustine if not earlier commentators suggsted that animal death was
present before our fall. Also, before the fall Adam and Eve were commanded
to subdue the earth, implying real responsibilities to change things after
they were pronounced "good". I have heard a suggestion that human physical
death could have been part of the original plan for humans as the
transition from earthly to heavenly existence. Human death as we know it
is certainly affected by the fall, but there may be glimpses of a better
version in a peaceful death in old age, e.g. the deaths of the patriarchs.
Although getting eaten by a predator is surely not a pleasant experience
for a deer, neither is starvation or disease.
The current system does work well if the most important goal is having a
diversity of living organisms surviving a variety of environmental factors.
David C.