I apologize for the disruption we caused you when rolling out Grafana 9. We are working on improving our releases to Grafana Cloud and also on making sure that errors due to breaking changes in a major release won't affect customers in the future. As a Grafana Cloud customer, you shouldn't need to read docs about breaking changes when we upgrade your instance.
Internally (in the Grafana team), we call it unified alerting because it is a unified UI for non-Prometheus data sources together with Prometheus alerting (and Loki/Cortex/Grafana Cloud alerting) and allows you to see all your alerts together.
- For non-Prometheus data sources, uses the Grafana alerting engine but also has an embedded Alertmanager. Can use the same routing, grouping, deduping and silencing features that Alertmanager provides but for data sources like InfluxDB or MySQL.
As Kyle says, we are sidestepping the template variables problem by decoupling alerts from dashboards. You can instead link from an alert to a dashboard or panel (or run book) and get a similar experience to the old alerting.
When you get a notification, you have a link to the appropriate dashboard and it is also easy to create an alert from a query in a dashboard. You can see the linked alert rule in the panel edit mode.
We are also working on an expression language to backfill other data sources. You can see the frontend version of this - transformations in 7.0. The backend version which will support functions like timeshift is in alpha for now. Hopefully it will be officially released in the near future.
We know that there are some gaps in the alerting feature (we dogfood it ourselves). The Grafana team will be focusing a lot more on alerting in 2020. For Grafana 7.0 in May, we are aiming to build better alerting that retains the simplicity of the current alerting but that will fill some of the those gaps. The new engine will decouple alerting from the graph panel and hopefully sidestep the problem with template variables. Once we have got further in the design stage then we will share more with the community about the proposed solutions.