đŹ Marketing Cloud Next takes care of your sending IPs automatically. But that doesn't mean you're off the hook for deliverability: https://mateuszdabrowski.pl/docs/salesforce/marketing-cloud/config/ip-warming-deliverability/
On @* Marketing Cloud Engagement * you have full control over deliverability, for good and for bad. On @* Marketing Cloud Growth & Advanced * the experience is more streamlined, but also controlled by Salesforce. You start on a shared pool of IPs, and you work your way out of it.
Once you cross ~5M emails/type/month, Salesforce rewards your achievement with a dedicated IP, and warms it on its own. Not much to do for you. No schedule, no throttling, no configuration. Marketing Ops dream? Almost.
There are still some important tasks on you:
đľ You still need basic configuration to enable your first sends. And it's a bit stricter than it was on MCE.
đ IP reputation != Domain reputation. A new sending domain (might) still need its own warming plan.
đ´ Monitoring is a must. It already was. Then it got must-er with tighter ESP bounce & complaint rate requirements. And now it is must-est with lower control over IPs and the impact of being demoted to the Gray Pool.
Full mechanics, the prerequisites checklist, and the monitoring options with setup guides are available now on my page.
Mateusz DÄ browski (mateuszdabrowski.pl) Forum Ambassador
I would say it will depend on the root cause. Some may be user-driven (poor-quality databases, compliance issues leading to a high complaint rate, high content spam score, broken email code, etc.) - and for those, SF has an answer: Grey Pool. But if everything is right and the deliverability rate is not matching the standard rates, then it will be on Salesforce (through a support ticket) to check the IP and potentially rotate.
In practice, I expect there will be grey areas of responsibility (like domain-related IP warm-up topics, or huge changes in send volume after already landing on dedicated IPs) that will need to be observed in real life.
Is it a better approach? If the grey areas will be truly limited to edge cases, IMO yes.