Allow Velocity Script Tokens in Webhook Payload

Currently, Webhook payloads do not allow Velocity Script tokens. Why not?

Using a Velocity Script token to generate the JSON payload for a Webhook would be very helpful. For instance, the JSON structure of my Webhook could vary conditionally based on Lead and/or Program tokens. Currently, if I want to perform different actions in an external API, I would have to create numerous Webhooks. I don't want to have a different Webhook for each variation of my API calls. I would like to use a single Webhook, but vary the payload using the conditional logic of a Velocity Script.

Desired

Webhook - Mail Item

{
     "leadId": {{lead.Id}},
     "sku": {{my.SKU}},
     "qty": 1,
     "address": {
          "name": {{lead.Full Name}},
          "street": {{lead.Address}},
          "city": {{lead.City}},
          "state": {{lead.State}},
          "postcode": {{lead.Postal Code}}
     },
     "data": {{my.Custom Script}}
}

Velocity Script Token - {{my.Custom Script}}

{
     "postcard_message": "Dear ${lead.FirstName},\\nYour subscription is about to expire on ${lead.subscriptionEndDate}.\\nRenew today!"
}

Velocity Script Token - {{my.Custom Script}} in another Program

{
     "brochure_image": "${my.brochureImage}",
     "brochure_copy": "${my.brochureCopy}"
}

Current

Webhook 1 - Mail Postcard

{
     "leadId": {{lead.Id}},
     "sku": {{my.SKU}},
     "qty": 1,
     "address": {
          "name": {{lead.Full Name}},
          "street": {{lead.Address}},
          "city": {{lead.City}},
          "state": {{lead.State}},
          "postcode": {{lead.Postal Code}}
     },
     "data": {
          "postcard_message": {{my.Custom Postcard Message}}
     }
}

Webhook 2 - Mail Brochure

{
     "leadId": {{lead.Id}},
     "sku": {{my.SKU}},
     "qty": 1,
     "address": {
          "name": {{lead.Full Name}},
          "street": {{lead.Address}},
          "city": {{lead.City}},
          "state": {{lead.State}},
          "postcode": {{lead.Postal Code}}
     },
     "data": {
          "brochure_image_1": {{my.Custom Brochure Image}},
          "brochure_copy": {my.Custom Brochure Copy}}
     }
}