The add-on LeTBS_MultiSelection adds some feature to select multiple AoEs for a skill and efficiently use them during sequences.

Basic Setup

Use the tag: X selections: type; [Help Text].
X is the number of selections the add-on will trigger.
type can be either append or distinct. With append, the final AoE is a merge of the selections. With distinct, each selection is unique and can be used differently during sequences.

Example: 3 selections: distinct; Select 3 areas

Prompt Selections During Sequences

The add-on adds a mean to request a selection during sequences. The sequence command "request_selection: skill(ID)" draws the scope of the designated skill and wait for the user to select an AoE.
The demo skill "Ally Teleport" uses interestingly this feature.