From the lens of an automation architect

The front end is in some ways easy and hard to automate

Synchronization can be a problem but object identification can get easier

API automation can be a challenge, since they are not designed to be consumed for folks other than developers

Dev and test environment creation can be old school, that means creating and tearing them down is hard

More points under each of these areas can be explored here:

http://quality-spectrum.com/legacy-products-automation-technology-challenges/