By moving the boosting into the actual spawning process you get several benefits:

• Lab code gets simplified
• boosting process gets simplified
• boosting is now possible at low RCL (provided you have the resources)
• you get the entire lifetime of the creep boosted

But also some not insignificant drawbacks:

• Spawn and extensions have to share their storge with the boosts
• It is very expensive to create a fully boosted creep and it takes a very long time
• It is a breaking change. (but that probably will root out a lot of inactive players and NCPs)

As an aside - removing NCPs should not be a Dev issue unless they become a huge problem. They are playing, and hopefully paying, customers. NCPs are a player defined issue, created by players, and should be "solved" by players.

I think it is fair if a underdog is able to use scrap minerals/compounds collected overtime to his advantage i.e. emergencies.
Those boosts are there to enhance your creeps and it should be difficult to obtain them not to use them.
Currently there is a unfair RCL cap that makes minerals useless under lvl.6 in a room.
It is unfair because it is possible to obtain minerals early on even if that depends on luck.

Also I think it is a good time to revisit this mechanic with the reveal of the coming factory draft.
That will change the Gameplay dramatically since it finally gives good reasons for players to specialize on specific tasks instead of pure economics or bulling others.

@KyraLee yeah I'm not worried about NCPs, it is just more like a nice side effect. Forces people to look at their code ^^

Everyone can code a transporter creep that puts it in labs, and some code to boost a creep.

That is exactly the problem that I'm pointing out, the lab requirement.
Boosting should not be bound to the lab since it is a refinement facility.
Have you ever heard of someone who is driving his car to the tire manufacture to get new tires fitted?
The spawn is the instants that handles creeps and it is inconsistent that it doesn't handle boosting.

And this change is mainly intended to balance a bit the tremendous power gap between RCL levels.
And energy doesn't need a cap it has already one 5~20E/tick per normal room.

Also by allowing less creeps to do more work the server load also may improve,
and don't come with BS arguments like "that is a insignificant improvement" every improvement counts regardless of how big it is.
That should be especially be true for the people playing this very game...

Unless we're talking shortly after respawn, in which case IMO that's a much too narrow window for such a sigificant change and you're not going to have boosts anyway.

It is a breaking change. (but that probably will root out a lot of inactive players and NCPs)

Rooting out a lot of inactive players is a terrible idea and doesn't mitigate a breaking change. Ideally their code will carry on running so that if/when they pop back into the game they still have some skin in it and don't have to start again. Having to start again from scratch will make some returning players completely switch off.

I think that boosting with the lab is inconsistent also annoying since you have to micromanage their contents.
Boosting in low RCLs allows to build fairly sturdy and useful outpost without the need to pump it up to full RCL8 if you are able to secure a supply route.
This opens up a lot of new Gameplay opportunities and IMO it is worth it.

I really couldn't care less.

I care, because an important part of the survival of any online game is player retention. In games with RPG/progress mechanics, if you carelessly destroy people's progress, you lose players.

This should be obvious and should not need to be spelt out.

Conversely, throwing a store on the spawns with enough capacity to store enough boosts to be effective will also trivialize the learning curve as the spawn would just become a level 1 storage. This would also trivialize the body size constraints creeps face with low level rooms.

Boosting, in my opinion, needs some help, but that has nothing to do with spawns. The wall of difficulty that is labs + terminal + market all at once needs some help, but that has nothing to do with spawns either.

You can argue that you should never put an invalid value into a RoomPosition, nonetheless, some people have been doing this for various reasons (e.g. find the space to the left of the current space by reducing pos.x by 1, then check afterwards if it's < 0).

It's broken several people's code.

The memory hack is different. If something is changed there, then it's ok to break code, because RawMemory._parsed is not documented.

But RoomPosition was documented and everyone works with it. It was expected to be an intermediate class to work with, with simple fields, not checked properties. Such an object should not be packed, cpu is more important here. So this change was very unexpected.

The point is, this was just an example that breaking changes seem to be acceptable if not all players will be affected. And again, if labs are still working, then MrFauls idea wouldn't be a breaking change.

The argument of Smokeman was, that logistics is difficult and boosting would be too simple with this change. And while I kind of agree with this, I'm not sure if boosting should be so difficult. Yes, everyone who masters logistics doesn't want to loose their advantage, but the difficulty for new players is already raising with power creeps and regional resources. Maybe we should consider some ideas to decrease this difficulty.

A player can use 3 labs from RCL 6, which means with the simplest of manual market interaction, a player can be making and applying T1 boosts as they also gain access to the extractor at this RCL.

If the spawn applied boosts, how would it work? Does the player need to remove the boost they have made from a lab, and move it into a spawn? The spawning method then gains a new parameter stating how much boost should be used? This sounds like more complexity, not less.

Furthermore:

• What interaction would this have with renewing creeps? How would I be able to spawn (say) an attack force, have them all renew to the same TTL, and then boost?
• This will add more complexity regarding spawn locations, as a creep will need to be spawned in a spawn that has the correct boosts.
• How many boosts, and how much of each can a spawn store? A creep can be using many types of boost at once, after all.

Even if I agreed with your idea, it is insufficiently detailed.

Also I really dislike the term "breaking change" it is normal for games to reevaluate its rules to adapt to new situations.(And so should its players)
I really don't get the fuss about API changes it shows only that the game is cared for.

The mineral mechanic was introduced as "higher lvl" experience but that isn't so much important now with the rise of PCs
The entire intention behind this change is to make the game more consistent (aka: Spawn handles all Creep related stuff, Lab does stuff with minerals)
and accessible for new and upcoming players.
Simplifying a bit the rules also makes things more complex there is a reason why Go took a cutting edge AI.

Of course, implementing what you're talking about in Screeps is not an option. This change would decrease the number of tactics and use-cases of spawning and boosting mechanics (the example is, you can spawn 6-9-12 50parts creeps, renew them to have the same ttl using the spawner, then boost with labs), increasing logistics difficulty at the same time. This is exactly opposite to what we're trying to achieve in game design.

Regardless of that, I thank you for wording your idea here on the forum. While it can't be directly applied to the game, it still can be the source of inspiration in some other activities.