I just step into AAI series and take time to make it work.
I then noticed the great game changing potential of this mod.
The RTS style control part is really great on offense, and it also feels more "righteous" than doing the tower crawl.
But the even greater part is the automatic vehicles.
There is a potential to insert a whole new layer of transport system right between belts and rails.
For example, use auto-vehicles to transport ores from some mining sites in a few screens sized area to a nearby train stop. This will save a lot of belt materials and reduce the rail network complexity.
Auto-vehicles can also provide an alternate solution for the main bus design.
So a playable vehicle transport system is really a great direction to advance.

However, the complexity of the circuit logic is the biggest problem here. Design a working circuit program is more like a self-chanllenging puzzle then a playable game mechnism.
For example, the simple patrol design, every waypoint need a unique zone mark. When the number increased, the zone signals will run into shortage quickly, and remembering which zone is wich is also a headache.
And if I use coord numbers intead, the new circuit will include a hell lot of constants, and a for each waypoint, there will need a position checking system. Such circuit is a nightmare to design.
Also heavy circuits are not very ups friendly.

So my idea is to use the vehicle-aboard computer style rather then the remote control center style.
Integrate the most commonly used features into the vehicle directly, and only left the simplest wo.rk to the circuits

Real Suggestions Begin
First, some remote control center improvements.
1.add a "waypoint" building, basicly a 1x1 lamp looking stuff. Every one of it should have a unique consistent id. It should be unstackable, thus when you reposition it, the id won't lose, and then you don't need to change the circuit setting.
The id and the position should be shown on the mouse over ui.
If possible, show the id inside inventory too.
When unit scanner read this id, returns the position signals.
When unit controller read this id, treat it as a position, and send the vehicle there.
Also unit scanner should return the closest waypoint id if there is one closeby. This is for checking if vehicle arrived the waypoint or not.

2."Ground Waypoint"
A 4x4 ground building, no hitbox. Fisrt, it should have every property that a waypoint have, and make sure its position is its center.
Second, this thing also work as a unit scanner.
Its target is the vehicle right on it. If there is multiple, then choose the one closest to its center.

3."Pause Signal"
While have this signal, the vehical should stop moving. Wait unitl the signal is gone.
With a Ground Waypoint, a Unit Controller, and some deciders, a nice vehicle loading station can be build.

4.option that disable the instant inventory transfer mechnism.
It is just OP, and not fit factorio's theme.
Let's use inserters to build a loading station descript in 3

5."Vehicle path control center"
A unit controller dedicate to control the movement of a vehicle.
It should have a nice ui that you can assign, remove, reorder waypoints.
Allows 3 mode: one-way, loop, round trip
It should have a on/off toggle, and always record the last visit waypoint, so that it won't lost after some state changes.
Every waypoint can be marked as a "waiting point", thus the vehical only allows proceed if the next waypoint is unoccupied. This should solve aome traffic jam.

6."Vehicle Computer"
Do the same thing as 5. But it is integrted into each vehicle.

Waypoints have been added now via the Path Remore Controller