I searched the forum and got the same question but with no answer. Does anyone have a reason why increasing OSPF External AD to 171 will not be ok?
yes you can do that. BUT the question did not specify that you need to fix any sub-optimal routing. hence it was not required.
I did the same. Its simpler, much easier to configure, plus it results in optimized routing, and fulfills the requirements - unless anyone else knows otherwinse. Now if we had any routes being redistributed into the OSPF domain (other than from EIGRP) this wouldn't work, but since we dont - it works beautifull afaik.