Microsoft delivered customer approval workflow with October release.

Please include all fields on customers form in this functionality and also let users to configure workflow approval requirements for new customers as well. (Considering retail, please also exclude customers created from POS app from this functionality.)

For new customers workflow, a simple solution might be:
1. Adding a checkbox in AR parameters to set all new customers to On hold = All.
2. Setting "Current" value in change proposals to All, "Proposed value" to "No"
3. Approval of workflow updates customer on hold status to "No".