... have you implemented a slave emancipation process in the first place?
Yes, we did that years ago already in RaR.
Slaves can become free over time by "Learning by Doing"-SubFeature.
(Through working long enough in a Profession.)
There is e.g. the "Freed Slave" (mechanically like "Free Colonist") which still preserves some of his bonusses for raw materials.
The "Freed Slave" can also become an Expert by LbD just like "Free Colonist".
... slaves serve very little gameplay purpose as it is.
It is a matter of gamestyle and if you know how to exploit the mechanic
in terms of scaling.
Slaves are very cheap labour. You could e.g. have
8 Slaves for the price of one normal worker.
Also Slaves have bonusses on raw materials which normal workers (Free Colonists) do not.
So they are often even better workers. Only real experts are better.
Summary:
Slave Strategy can be
very very efficient if you play it right simply by the sheer amount of workers you can have.
Also they are better workers than "normal colonists". Only Experts are better for raw materials.
Yes it is annoying that they run away, but the
"scaling effect" if you play large is really strong.
Also you can
prevent them from running away and they are also
going to become free eventually.
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But yes, there are also strong cons.
1) Slaves Running away to be caught again. --> low XP when recaptured (capped)
2) Slaves Revolting so they have to be destroyed. --> normal XP when destroyed (not capped)
But as I said, these can be countered.
(And might even create XP for your troops.)
----
In other words:
It is about game style and
knowing how to use "Slave Strategy".
The "Slave Strategy" has strong pros but also strong cons.
It is a strategy that produces enormous outputs of raw materials.
But you also constantly need to manage and pay attention to it.
"Slave Strategy" is
not a beginner strategy or casual player strategy.
It is more of a hard-core role player strategy that wants to min-max.
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WTP offers many different game strategies.
It is up to you which ones you like or do not like.
But all of them are valid
if you know how to use them.
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Personally I use "Slave Strategy" and have benefited from it.
But I do not focus on it, but
use it "opportunistic", when it is offered.