Using Ansible to save Cisco (IOS, NX-OS, ASA) configs

I know this is only tangentially a networking question, but I figured networkers are more likely to have come up with solutions to the challenge below.

We started using Ansible modules (ios_config, nxos_config, asa_config) to save running config of our network devices to an Ansible server. I have a couple of annoyances:

1. The playbook runs daily and saves the config to disk regardless of whether there have been any changes.
   • I looked at the documentation and didn't see a way to conditionally backup configs.
   • I'm thinking of using python or bash to do a diff between saved files and delete files that are identical.
2. The filenames are `<host>_<date>@<time>` by default. I'd rather drop the `<time>` portion but am having a hard time using a variable from a different play to save the configs as `_`. Has anyone come up with a solution to this? I'm thinking of using `sed` to rename files, but that strikes me a clunky.

To end on a more positive note, if anyone has plays they run for their Cisco or F5 LTM gear (not config changes), or clever tricks to massage the data, feel free to share.