What is too many bolted routes in a space?
To me, to name a few situations, if you see a lot of hardware in rock where a climb could be led especially easily on good traditional gear, or if you can no longer tell just looking at climbs which bolts were placed for one climb over another being so nearby, and if an original line is no longer obvious with bolts distracting climbers to take another path off it. Or if you just walk up to a place and see anchor after anchor catching the sunlight..., if they could actually have been shared anchors. There are many caveats to all this probably, so just saying in general. Seen bolts for what looked like sit starts lol...
I find it exhausting to talk about every single bolt in terms of where it would be better placed and how it upsets an ethic except in obvious cases which happen. Then you hopefully climb the route(s) to really be sure to better understand the situation if possible and see if you get the rationale, or not.