@bdunbar79
Sorry, but why even bother with people who make such comments?
Even if someone does not know exactly what he is talking about, by implying you are and then making such a cynical comment should be a reason for people not to bite/comment on it.
I think he was just hoping for such a reaction.
OT, I think the 200-400 is a gem, but will probably only be bought by the real pros or people with enough budget to own 2-3 big tele's. Having it as your only big white because your ''budget limited'' would not work for me.
The 400/600 would make more sense from financial perspective.
Also 200-400 is 60-70% more expensive than the 300 2.8, while the latter has better/equal iq at 300-420 and 600 where the 200-400 goes to 560. Putting on converters all the time is not realistic.
With the money and weight you save you could get a 120-300 or 100-400 on a second body if flexibility is really needed.
Flexibility is worth it that you lose 2.8 and little bit of IQ ( however slightly ), but the the increased price over the 300, and price equal to the 400/600 means it is a hard lens to justify(for me). *** Edit the 200-400 is equally priced to the 600 here, and 1100 euros more expensive than the 400 f2.8
The nikon 200-400 makes the choice a bit harder , it is 15-20% more expensive than the 300, yet the 400 2.8 is 40% more expensive than the 200-400. There i did decide to get the 200-400 for it's versatility and price!
If it was as expensive as the 400, I would have chosen the 300 or 400, not the 200-400.
If budget was less or no issue, I am sure the 300 2.8 , 200-400 and 600 would be with me.
Even then I would probably bring the 70-200, 300 2.8 and 600 on safari and leave the 200-400 home.
Switching between bodies is not that time consuming , situations where wildlife runes straight towards you is also rare , and as the cynical poster has suggested , the 200-400 with its bad servo tracking would probably miss such a shot

LoL
And a good guide + off roading ability will mean you are not in such a situation, because that is basically driving prey to predator and not very natural hehe
The times we did encounter chases/kills it was parallel to our position , or driving along(i.e) different directions while driving.( It is very hard to keep(or even get) a 400mm 3.6kg lens on target when driving 30-40km/h in the bush , for me it came down to luck to get a few shots in). If there were no seat belts it would have been impossible because if the driver hits an aardvark hole you and equipment will tend to go airborne !