It's not surprising that it's impacting other services in the region because DynamoDB is one of those things that lots of other services build on top of. It is a little bit surprising that the blast radius seems to extend beyond us-east-1, mind.
In the coming hours/days we'll find out if AWS still have significant single points of failure in that region, or if _so many companies_ are just not bothering to build in redundancy to mitigate regional outages.
I'm looking forward to the RCA!