Ritual sacrifice is nearly universal in religious history, and human sacrifice quite common. Nothing whatever prevents its occurrence, even as a common phenomenon, among "developed" societies, unless one jury-rigs the question by defining "developed" to exclude human sacrifice.
As a first approach, one ought to conceive of human sacrifice as a passage-rite, or rite de passage, as Arnold van Gennep indelibly termed them. Passage-rites transition the subject from one recognized social state to another, by way of a mediating third phase in which highly-valued cultural conceptions and norms are manifested to all concerned during a delimited focal event.
For example, girls' pubertal rites transition the subjects from "girl" to "woman" by way of a mediating "liminal" phase in which many of the culture's deepest notions of what women are -- their roles, their bodies, their meanings, their functions -- are proposed to the ritual subjects for consideration. The mode of such presentation varies widely, but (at least Victor Turner's analyses) usually balance freedom -- the freedom to discuss and/or think about the presented norms and ideals without ordinary restrictions (you can't talk about those things in public, it's wrong or dirty or blasphemous; you can't question those things, they're just true because that's the way the world is; etc.) -- and constraint -- the constraint imposed by the structure of the rite such that the neophytes emerge having accepted the near-absolute value and validity of those cultural norms.
In other words, a passage-rite
- transitions the subject(s) from State A to State B
- by way of a sharply-delimited liminal phase
- during which phase certain culturally-important norms and ideals are presented strongly
- for free consideration and interpretation by those to whom they are presented
- with the constraint that interpretation must ultimately reinforce the social norms and ideals
- the symbolism of transition from A to liminal is commonly that of death (one dies to State A)
- the symbolism of transition from liminal to B is commonly that of birth (one is reborn into State B)
If human sacrifice is construed as passage-rite, in the same way as funerary ritual is, then a few points immediately become clear:
- State A includes "live" and State B includes "dead"
- the liminal phase is defined such that physical death occurs in its purview
- the norms and ideals almost certainly have to do with the nature of life and death, but also with the status or qualities of those who undergo the rite, as well as possibly those who order, perform, or otherwise engage in the rite
- the free consideration and interpretation is almost certainly not confined to the initiatory subject (the victim)
- entrance into State B is likely understood as some sort of rebirth
In Classical Mesoamerican societies, a number of core principles linked these factors. For one thing, human beings and their life-cycles were analogized to maize. Maize, after all, reaches its maximal value when it is harvested and ingested; just so, human life is incomplete and problematic until its has ended and the body/spirit/blood been ingested. On this understanding, "ingested" includes not only cannibalism -- which did occur, in token symbolic instances, across Classical Mesoamerica -- but also being eaten by certain gods, as well as having one's body be absorbed into the earth as fertilizer for new crops/life. It is unclear, but sexual intercourse may in some circumstances have been analogized similarly, with the vagina becoming a mouth that eats male spiritual essence -- this links up, arguably, with the regular appearance of vagina dentata symbolism throughout a wide swathe of American mythology.
The only point that appears to prevent regular human sacrifice, in most modern conceptions, is that one "obviously" should not kill other people on a large or regular scale. Here again Classical Mesoamerican examples demonstrate the incoherence of this claim. Warfare was normally conducted using weapons poorly adapted for killing one's enemies, but beautifully adapted to rendering them unable to fight. Battle was normally a matter of defeating one's enemies and then dragging them home as slaves. In later Aztec society, a very large percentage of such slaves were sacrificed, but the difference between this and earlier formations seems to be a matter of percentages and scale. The point is that if you have defeated your enemy on the battlefield, in most open-warfare situations, he is dead. The fact that, in Classical Mesoamerica, he may not actually be physically dead, does not change the point. If a battle between 500 warriors on each side concludes with one side having 150 escape and the other 350 die, does it matter whether they died in that moment on the field or a few weeks later on the sacrificial stone? They're dead either way. Indeed, one could argue that death on a battlefield renders the warrior anonymous, strips his individuality and significance from him, as he becomes nothing more than a statistic. By contrast, his sacrifice on the stone grants his life and his strength specific worth, and he is given an opportunity to face death in a way he considers proper. Sacrifice, in this view, is essentially battlefield cleanup by other means.
This brings us to the question of "honor." We often encounter a notion that one should honor the dead, and we are continually enjoined to honor brave soldiers who risk their lives and die on the battlefield. In the Classical Mesoamerican conception, such honor should not be done at a distance, nor only by one's own people. One should honor one's opponents for their bravery and warlike qualities, as well: if your enemies are not worth that honor, why fight them? why risk your own warriors' deaths in combat against meaningless enemies? Those whom we defeat in battle we honor in sacrifice. Through sacrifice, several things happen. First, we give great power and strength to our tutelary gods, who support us in our endeavors. Second, we honor our brave warriors who capture their enemies in battle. Third, we return the mighty bodily power of our enemies to the earth, where it fructifies our crops and our polity. And fourth, we grant our brave enemy an opportunity to show his bravery and worth, to demonstrate his power and significance, before a wide and admiring audience of our own people. We know very well that he would do the same for us, for he comes of an honorable and mighty society -- albeit not so mighty as ours. And so we know that, if he is truly a worthy opponent, he will march to the stone demonstrating his power and his lack of fear, thereby ensuring that all our gods will rejoice in his life and his death.
There is a lot more to it than that, of course, but I wanted to present a conception under which human sacrifice depends on positive notions, both metaphysical and socio-political. One could certainly argue, as other answers here have argued, that US-style death penalties, abortion, and a number of other phenomena could be read as human sacrifices. The questions at stake are not at base ethical: it's a matter of the symbolic construction we impose in order to interpret these behaviors. Indeed, I would argue that US-style capital punishment is far less ethical, in every possible sense, than was Aztec sacrifice, because (a) we don't think that the dead body is worth anything, (b) we pretend to think that those who revel in revenge are in the wrong, (c) we deny the utility of the performance to any wider audience, (d) we treat it exclusively as a punishment. Thus nobody gets anything positive out of capital punishment: the only "good" is the removal of a negative. But I don't like double negatives in rhetoric, and I really don't like them when it comes to people.
Short answer: yes, human sacrifice is entirely possible, and indeed is arguably practiced in the United States as a legal process (albeit a very incoherent one). To build human sacrifice in your worldbuilding project, focus on what it does positively. People die all the time; whether they die under a knife or by being cut down on a battlefield, they're dead. So the difference that makes human sacrifice interesting is that it puts a focus of control on the death, thereby granting it higher-order meaning. Once you work out your processes of initiation, the fundamental symbols and mysteries at stake, you may begin to wonder whether your sacrificing society is any less "developed" than is the United States.