Ok, let's screw it a bit more.
Accepting this mechanics, would mean that ZoC do not expand on improvements, so you will need lots of more outposts to get the resources and your cities safe.
Currently, it is necessary spamming a lot of them to connect cities, etc.,
Can you imagine how many pioneers would be needed only to build outposts to protect cities (give them safe ZoC) with this mechanics?
As said above, you fix a problem but other things might get worse.
What will happen with cities built in a tile surrounded with swamps or mountains, with no space to build? Failed cities? And don't tell me don't build there, or I will tell you don't snake.
For me, this new mechanics might be ok, if:
pioneres could build outposts without consume OR
give +1 LOS to the outpost, to not needing so many of them. The High Vision upgrade would give another +1 LOS, so what?