NAT is a problem with dual routers because the tables in NAT don't get shared between the routers.

That topology will break NAT if the traffic is asymmetric. Asymmetric traffic will come from the WAN to the wrong router and get passed to the correct router on an inside interface instead of the outside interface, so it will never translate.

NAT is a problem with dual routers because the tables in NAT don't get shared between the routers.

That topology will break NAT if the traffic is asymmetric. Asymmetric traffic will come from the WAN to the wrong router and get passed to the correct router on an inside interface instead of the outside interface, so it will never translate.

EDIT:

This is your drawing modified for what I mean. The link between the routers must be the best path from one router to the other.