The map now displays lamps as blue like most other constructed entities.
A lot of people use colored lights or circuit-controlled lights to indicate status. I for example have a 'control panel' where I can quickly monitor stock levels and similar local panels for plants that show input and output stock levels:

Since the zoom-to-map was reduced in the sense that you need to zoom in pretty far to activate map mode, this is a less effective way to get a general picture of base performance.
[Alternative suggestion: allow mods to change the color of an entity on the minimap, so this can be modded in and a mod like bottleneck could also change the color of plants on the minimap to indicate status]