There is a difference between the standard clone children and the Masters.
===Skip this if you know how OP2 reproduction works===
From reading the novellas, I gather this to be how children are produced:
1. take two samples (Male and Female), at least one of them from the gene bank at random. By using random genes from such a large group of samples, the colony avoids the problem of inbreeding.
2. Mix the samples under lab conditions to simulate the reproductive process. This results in the child getting the standard mixture of genes from their "parents".
3. I assume the genes are somehow put into an embryo.
4. Either implant the embryo in the mother, or maybe let it grow in a tank, I don't know.
The people resulting from this process would technically have been "cloned", but since random DNA is used in step 1, you don't just have copies of people walking around, and you retain a diverse society with many different kinds of people.
===End of reproduction recap===
The reason the Masters were the bad guys is not that they were clones, but that they wanted to remove step 1 from the cloning process and just start copying people whom they thought were "better", instead of allowing genetic diversity. They weren't "crazy" just because they were clones, they were "crazy" because of the way they wanted to use cloning.
Once again, I think the central question should be: Even if you do have a set of cloning tanks, and have the technical ability to double the birthrate, will the society be willing or able to handle it?
Having children would be a choice in the colony as much as it is now. That is: If a couple wants two children, they will have two. If they want one they will have one. What happens when another essentially unwanted child is produced as a byproduct? Will the parents want to take care of more children than they wanted in the first place? Can the colony government force them to? Can robots raise a child to adulthood? Will that child resent not having human parents?
Considering all the problems it would cause to just artificially increase the birthrate with clones, it would probably be a better use of resources to design more efficient buildings, better AI's, etc. rather than screw [<-teeheehee] around with human reproduction