#4444 originally changed the cumulative to delta processor to default to converting all cumulative metrics to delta. This behavior was reverted and currently the configuration requires a user identify each cumulative metric by exact name for conversion to delta.

One proposal is to implement regex support #4444 (comment).

Another thought is to do away with the metric name configuration entirely. That is, by installing this processor into your pipeline you're declaring you want delta metrics. This thought is inspired by open-telemetry/opentelemetry-specification#2032 where the ability to configure aggregation temporality at the view level in an SDK was removed. Aggregation temporality would be overridable at the metric reader/exporter.