forum.freeciv.org

In my opinion, Freeciv should give modmakers a new points type, called engineering points. This would be like science points - gathered globally, but engineering points wouldn't have special tab or something like that. Also engineering point will be spreading as gold, so player couldn't perform any action if there no amount of engineering points. Some buildings, like University could provide engineering points. Specialist could also provide engineering points. We can call this kind of specialist labor. Engineering points would be lost on each turn.

Ideas about engineering points:
1. Workers task
In Civilization: Call to power exists engineering points. It could be used to build terrain improvements or to transform terrain. This action could be taken from world map. In this forum were many threads about ridding off worker unit and add mechanism similar to this in Civilization: Call to Power.

Workers couldn't start action if there insufficient engineering points, so it connects both ideas - using workers and global points. That's quite normal railroads or roads must be designed by engineers. Fortress would require engineering points too.

2. City improvements/wonders
That's quite normal buildings must be designed by engineers. Some buildings, like superhigways, city walls, coastal defense would require engineering points. Similar to terrain improvements, player require some amount of engineering point to paid to establish production of building.

3. Immediately repair units
Player will be able to immediately repair some kind of units, like naval units, tanks, bombers, fighters, etc. It will cost engineering points too. I doubt it is fair to paid from global engineering points rather than points provided by city. (Maybe allow to repair human units by food -in my opinion repairing units like warrior should require food - in medieval attacker takes access to food firstly, so defense are weakness)

4. Support units
Some units, like tanks, bombers, naval units will require engineering points to exist. Tanks can broke off by using it rather than taking damage.

5. Some rulesets may require to use science points instead of engineering points.

6. City radius square
City radius square could depends on engineering point produced by city - someone must design city infrastructure, like roads, severs system, etc..

7. Homeless citizens
If city growth, some engineering points are subtracted from engineering points provided by city. If city don't have enough amount of engineering points new citizen would be unhappy (homeless) until city don't provide amount of engineering point required by new citizen.

Honestly, I think this would over-complicate things, especially if there's a differentiation between global and local EP, and especially for AI development.
(1) The workers are already some kind of engineers (heck, they're upgraded to them once Explosives are known), so I don't think this is really necessary.
(2) We already have production points (shields). The planning of buildings is done by the citizens. Just that the citizens are assigned to some area around the city doesn't mean that 100% of them work that land, because then, we'd also have to introduce specialists for garbage men, retail workers, bankers, builders etc. ─ I think it's better to just assume that some part of the people does it.
(3) I think for quick repair, production points/shields would be more logical. You don't need to re-invent the blueprints for the machine you're trying to repair; you only need to build replacement parts (I got that right, EP are produced by Universities etc., so they're more mind work that actual physical stuff?).
(4) See point (3). You could already make a ruleset where mechanical units have an upkeep of two shields instead of one.
(6) City radius is fine as it is currently in the experimental ruleset (save for patch #5983, but that's minor). Also, the city radius is just the area around the city which can effectively be worked by the city, not part of the city itself. Also, if the city radius would be determined by specialists, it would be way too variable for anyone to reasonably code an AI for it. It would also make everything more difficult for players, since there's not four different radii to work with, but possibly hundreds.
(7) New citizens after the first four are unhappy by default anyways (City_Unhappy_Size). Also, city growth is already limited through means of Aqueduct and Sewer system, you could just as easily add multiple "Suburb" city improvements that need to be built before the city can grow to a certain size.

All in all, I think it isn't necessary at all and overcomplicates things.

I think that University will increase EP produced by city on each turn, so it will be more realistic(in university we have invent new technology, which makes developing/building buildings, roads, etc. simpler), but some other buildings will add EP to EP produced by city.

That's will be more realistic. By building many cities we will have many EP(many hands to work,), but we can also build buildings to provide more EP - which one city we can collect EP to, for example build wonders.

About repairing units with EP, you have quite right, but imagine at naval units(like submarines) we have engineers.

If Freevciv team will decide to not apply EP, they should consider using production points from homecity of workers to start build terrain improvements. In my opinion using production points is worse idea, because in game could exist homeless workers.

This idea looks like rejected.

I think, that city walls should have energy and engineering points could restore energy of city walls. When we selecting to build city walls, we can select a level of city walls. Level of city walls will increase engineering points needed to produce city walls and population of city will increase of cost of engineering points to produce city walls too. When city walls energy drop below 0, city walls should be destroyed. Each attack by catapult or something similar to city will decrease city walls energy.