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.
I just wanted to extend my thanks for this new feature, it will be really, really appreciated. We have Grafana monitoring everything from your usual cloud stuff, down to the temperatures of cryogenic fridges. Being able to configure alerts more dynamically and clearly is going to make my job a lot easier.
Can't wait to fire this up and start re-doing all my alerts.
However, it does now support queries like `host=*` with multiple alerts instances per host from one rule/query. E.g. https://github.com/grafana/grafana/issues/7832#issuecomment-...