The reach argument holds even more true for MFT with its x2 factor.
I organised a 920mm reach but wouldn't do more than play with it becuase with the 'safe' wildlife I occasionally shoot I will get better results with a much shorter lens from a hide.
With Andre being in South Africa I guess he is thinking of 'Un-safe' animals from which you need to keep your distance although if you can entice the animals to near your vehicle then FF and a short lens will be better ... same as me working with APS about 18" from the birds rather than my 950mm reach bridge camera.
The answer I think is how you intend or are able to go about it.