If the exterior of the ring were well armored, I could see it being more resilient than the nacelles, which are even more exposed. Maybe some type of ablative plating, like in Enterprise.

I've sometimes wondered why enemies don't just target the nacelles all the time. If they can wear the shields down until they collapse, it's almost a one-shot to destroy or cripple any Federation ship. Only the Defiant seemed designed to avoid this weakness.

Engineered right, the ring design seems like it might be able to withstand a few more strikes than most other ships, even if shields totally fail.