I imagine that when someone working on the development team comes up for air they’ll comment on this officially.
This type of logging is happening for me on several Connect IQ devices I’ve used with my Fenix 5 so suspect it’s relatively easy to accomplish. IOW, I have a single CIQ metric displayed on my watch, but after syncing see 4, 5 or X from this device in the Connect portal.
This is a more substantial work effort and I believe impacts which devices can be targeted. Presumably that’s why many of the data fields in the Connect IQ Store that display more than Garmin’s default of 4 fields have their metrics hard wired and we don’t get to choose. Hard coding them may workout for some, but is likely the wrong combination of metrics for most.
Being limited to either 4 data fields, or accepting some larger number that others have chosen has been a source of frustration for me.
My vote would be to see a typical Connect IQ Data Field that allows us to chose 2 per activity, whatever 2 we want, and over time the community can let rS know what we’d find most useful.