We use a custom field at Idea level for sizing the efforts estimate of implementing a received idea. When we convert a selected idea into a feature, there should be an option to link this custom field to the Estimate field for Feature. This would ensure that effort estimation is done only once at the Ideas level, and this is eventually pushed to JIRA.
Thank you for the request. If you use the same custom field name and key for Ideas and Features, you can transfer the values from your custom field from Ideas to features (upon idea promotion).
At this time, we do not have plans to specifically map an idea custom field to the Feature estimate field based on current priorities, community feedback over time and the available workarounds.
We hope that the mentioned workaround can help.