Can anyone tell me if there is any plans to add this feature (Im aware some asset store plugins contain it)?
The EXR format for lightmaps creates serious artifacting and/or degradation when changes the textures resolution in Photoshop. Unless anyone has a workaround for this? Changing in and out of the EXR format doesnt seem to help.
Thanks for your time 
You can already manually increase the texture Size of the lightmaps if you want to. usually it’s not a matter of the texture size for lightmaps unless you have really large single Polygons that need to be lightmapped.
If you feel you need to have a larger Lightmap Size: mybe give this one a try:
http://forum.unity3d.com/threads/56435-light-map-max-at-1k-solved