No Temperature Value

Yes, I have the same issue.

The internal temp hasn't ever been included in the fit file for the vivoactive devices, and it's know to be off a far amount as it's impacted by body temperature.  If you want a much accurate value for Ambient, use a tempe.  It could be Garmin was getting too many calls about the internal temperature being so far off and they removed it from the data field.

temp data field still there, but it doesn't display any information at all.

It does if you have a tempe.  The external temperature sensor.

What I'm saying is the removed displaying the (usually inaccurate) internal temperature in the data field.

My Wife would like to know the Water Temperature while swimming on the 4s and show the room Temparature if it is not on her wrist.

I have the 945 and I like this informationen very much, it works great.

It should be no Problem the same on the 4s to realice