Sure, I mean, we could talk about

• dynamic inventory on AWS means the ansible interpreter will end up with three completely separate sets of hostnames for your architecture, not even including the actual DNS name. if you also need dynamic inventory on GCP, that's three completely different sets of hostnames, i.e. they are derived from different properties of the instances than the AWS names.
• btw, those names are exposed to the ansible runtime graph via different names i.e. ansible_inventory vs some other thing, based on who even fuckin knows, but sometimes the way you access the name will completely change from one role to the next.
• ansible-vault's semantics for when things can be decrypted and when they can't leads to completely nonsense solutions like a yaml file with normal contents where individual strings are encrypted and base64-encoded inline within the yaml, and others are not. This syntax doesn't work everywhere. The opaque contents of the encrypted strings can sometimes be treated as traversible yaml and sometimes cannot be.
• ansible uses the system python interpreter, so if you need it to do anything that uses a different Python interpreter (because that's where your apps are installed), you have to force it to switch back and forth between interpreters. Also, the python setting in ansible is global to the interpreter meaning you could end up leaking the wrong interpreter into the role that follows the one you were trying to tweak, causing almost invisible problems.
• ansible output and error reporting is just a goddamn mess. I mean look at this shit. Care to guess which one of those gives you a stream which is parseable as json? Just kidding, none of them do, because ansible always prefixes each line.
• tags are a joke. do you want to run just part of a playbook? --start-at. But oops, because not every single task in your playbook is idempotent, that will not work, ever, because something was supposed to happen earlier on that didn't. So if you start at a particular tag, or run only the tasks that have a particular tag, your playbook will fail. Or worse, it will work, but it will work completely differently than in production because of some value that leaked into the role you were skipping into.
• Last but not least, using ansible in production means your engineers will keep building onto it, making it more and more complex, "just one more task bro". The bigger it gets, the more fragile it gets, and the more all of these problems rears its head.