My brother was part of our posse on that trip with his Safari tank-equipped 690. And it went down on the rocks more than a few times. So yes, in principle I do agree - a unitary tank is tougher, but it does depend a lot on the mounting system. Safari generally have very solid mounting. And an advantage of the split tank is if one side punctures you can shut the tap and keep the other side intact.
The Acerbis 20l tank on the current 450/500 is way weaker than the old 525 one because it's much less well braced. I broke one on Amageza 2014, and I'm not the only one I know of, so strength of the system really comes down to multiple factors, I guess. This new Safari split system looks like it carries the fuel way down low, which will be excellent for handling.
What's always put me off the Omega system is the rigid, fragile carbon/fibre construction. I guess you can repair it, but seems much more fragile than the poly tanks.