In my slot values I use lots of synonyms and it would be much easier to maintain the annotation sets if I could specify the canonical string for the expected slot value. In other words, if in my slot value definition I have the following value:

{
  "name": {
    "value": "human",
    "synonyms": [
      "girl",
      "boy",
      "woman",
      "man"
    ]
  }
},

I'd love to be able to write in my annotation set

utterance               Intent                     slot[creature]
I want to be a boy      CreatureSelectionIntent    human
Let's try a woman       CreatureSelectionIntent    human

The canonical values are resolved at some point anyway, and my skill uses the canonical values when they are available:

"slots": {
    "creature": {
        "name": "creature",
        "value": "girl",
        "resolutions": {
            "resolutionsPerAuthority": [
                {
                    "authority": "amzn1.er-authority.echo-sdk.amzn1.ask.skill.***",
                    "status": {
                        "code": "ER_SUCCESS_MATCH"
                    },
                    "values": [
                        {
                            "value": {
                                "name": "human",
                                "id": "***"
                            }
                        }
                    ]
                }
            ]
        },
        "confirmationStatus": "NONE",
        "source": "USER"
    }
}