I doubt the extinction of the human race via a runaway technological event will turn the planet into a wonderland paradise for the rest of the species that inhabit our planet.
The planet itself, being a rock, doesn't care, at all.
In the long run, life on Earth would expand from the extra CO2 in the atmosphere. Pre-human CO2 levels were on a long downward trend, likely just a few million years from dropping too low for photosynthesis.