He's not everyone's cup of tea but interestingly the Ender Series actually feature a virus much like the ideas you describe, which communicates between it's own individual organisms and intentionally restructures existing biospheres.
Unfortunately OSC's grasp of evolutionary theory is shaky and suggests that all organisms would inherently tend to act towards a Gaia like optimisation of the biosphere, essentially having "natural" evolution driven by the need to regulate the effects of climate shifts rather than a more mechanistic, intentionless (and realistic) conventional view of gene selection.
Of course organisms would instinctively act to protect their biosphere. If you lived in a biosphere where humans were mucking up your environment causing your species to die off, wouldn't you find a way to regulate the effects of climate shifts to reduce the number of species causing yours to die off?
If a large group of viruses suddenly realized that their numbers were dwindling and that they could no longer hear the song of their entire viral species using quorum sensing, wouldn't you think they would do something about it?
Most of the time the viruses will go into spore mode until the environment is more favorable. Just like the Tardigrade goes into a type of hibernation until the environment is more favorable.
Eventually though, one of the viruses is going to have an, evolutionary snap, if you will. Instead of simply becoming spores and cowering away from the fight, the virus would come after humanity inflicting severe causalities in the human populace until us humans got their message. At that point though the virus would have developed human emotional traits, such as ego and hate. Traits that are merely chemical stimulus to begin with, traits would make the evolved virus part of natural selection, rather sentient natural selection.
Natural Selection - the process whereby organisms better adapted to their environment tend to survive and produce more offspring.
In this aspect an organism has adapted to survive its environment by becoming a spore until more favorable conditions exist to produce more offspring.
Sentient Natural Selection - the process whereby organisms that have adapted to their environment and have survived for millions of years by producing offspring plan and devise ways to completely eradicate another organism totally that is limiting the organism from producing offspring.
In this aspect an SNS organism has adapted to survive its environment by systematically eradicating another SNS organism that is threatening its offspring, while the SNS organism is producing offspring as well as the SNS organism going into spore mode to ensure its species will survive the environment. When the environment, war, is finished or comes to a stand still, spores of the SNS organisms begin reproducing, hoping to gain an advantage over the other SNS organism for dominance.
Most of the time viruses and bacteria go into a state of dormancy based on climate reasons mostly, too hot, too cold, too wet, too dry. The SNS organism however would adapt and even possible change the effects of climate in their favor. One area could be that the virus develops a new means of producing a lot of methane gas that would cause humans, for example, to slowly suffocate over time. Thus the SNS organism would adapt and control its environment to ensure that the organism effecting the SNS organisms environment, in this case, humans, are eradicated.
Most viruses seek out environments in which their produce offspring. The really nasty ones are able to effect the climates to reign supreme. Once viral supremacy has been achieved the SNS organism would go into a state of dormancy as it returns to a pre-war level of Natural Selection.
