Do you think Sara actually deserved the promotion?
do you mean the promotion in s4 or in "immortality"?
in s4, i think we don't have enough information to make a determination.
without knowing exactly what duties and responsibilities the "lead csi" position entails, it's impossible to say how qualified sara may or may not be for it based on what we see from her on-screen.
at no point during s4 does the show clarify what a lead csi actually is/does.
honestly, it's unclear how the position differs from being a supervisor or assistant supervisor, why it's not simply a matter of seniority, what the scope of responsibility would be for the person who had it, and even where and in what capacity the person holding said position would be working within the department hierarchy.
for example, is there one lead csi per team or is there one lead csi for the entire department?
unfortunately, the fact that there is ostensibly no lead csi that we know of prior to s4 (and never is one afterward, either) means that there's no way for us to extrapolate.
that so, it's somewhat impossible for us to judge whether or not sara would be a good fit for such a role.
she is generally an exemplary csi who has a high solve-rate on her cases, being both a hard worker and a smart one. she is also a good teacher (as we see from her as she helps to train greg in s4/s5). however, one weak spot on her résumé is that she isn't very politic and her people-skills sometimes leave something to be desired, particularly when we compare her to nick. she is also an unknown entity when it comes to fulfilling administrative duties, as she has never been in a leadership role prior to this point.
if the key position were all about individual performance and casework or even involved an element of teaching, then it's possible that she would be very deserving of it.
however, if it were more of a managerial position that might require her to deal with personnel issues and/or be involved with administration in the department, then maybe nick would indeed be the better fit for it over her.
frustratingly, grissom's ultimate decision regarding the position offers few clues to us about sara's level of qualification for it overall.
by his own admission, he chooses nick over sara mostly based on the criteria that nick seemingly doesn't want the position, whereas sara does.
which is, as sara points out in episode 04x22 "no more bets," a "stupid reason."
however, whether the implication to this decision is that nick is actually more qualified than sara is based on all the potential criteria points PLUS the fact that he doesn't want it, that nick and sara are otherwise "neck in neck" in terms of qualification but nick's ambivalence about either getting the position or not is the thing that pushes the needle more in his favor, or that sara is actually more qualified on paper but grissom still nevertheless chooses nick over her because he likes nick's attitude better, we honestly can't say.
the whole matter is, of course, complicated by the fact that throughout s4, grissom, based on his largely subconscious desire not to show sara favoritism, repeatedly thwarts sara's efforts to distinguish herself and bolster her résumé, while simultaneously doing all he can to build up and support nick.
after he turns sara down at the end of s3, grissom spends all of s4 [unsuccessfully] trying to keep his distance from her and disengage from her emotionally. however, his attempts to move on prove futile, because no matter what he does, he can’t change the fact that he loves her. the more he realizes that his efforts to disengage from her aren’t working, the more he panics, and the more irrational his behavior towards her becomes.
that’s why, during s4, grissom so often pulls sara off career cases while allowing nick to work career cases solo—i.e., because he is trying so hard to put distance between himself and sara and to prove to himself and sara that he isn’t ruled solely by his feelings for her.
of course, the irony is that in trying to prove that he isn’t ruled by his feelings for sara, grissom actually proves how very much he actually is.
every action grissom takes towards sara is personal, whether he believes it is personal or not. he’s not even consciously aware of what he’s doing, but the truth is that every time he finds himself wanting sara, he physically sends her away from him, which usually means she ends up at another crime scene, off whatever big case he’s working (see, for example, what happens in episode 04x02 “all for country”). likewise, whenever he finds himself wanting to give sara special treatment, he reacts by forcing himself to get tough on her and read her the riot act (such as we see him do in episodes 04x07 “invisible evidence” and 04x08 “after the show,” for example).
in the meanwhile, he continues to manage nick according to merit, meaning that whenever he feels nick has earned a privilege or proven himself worthy, he rewards him (see, for example, episode 04x11 “eleven angry jurors,” when grissom allows nick to reopen an old case and investigate it solo, then gives nick credit where credit is due when nick solves the case using creative investigative methods).
by constantly suppressing and thwarting sara while at the same time encouraging and supporting nick, grissom gives nick an unfair advantage over sara in the race for the promotion without even realizing that that’s what he’s doing (or being consciously aware of his own motivations for doing so).
nick continues to rack up career cases, professional accolades, and grissom’s personal favor, while sara just can’t win for losing and is unable to catch a break, even though the quality of her work and work ethic remain as impressive as ever.
that so, even if it is the case that nick does ultimately end up looking like the better candidate when all is said and done, one has to wonder to what extent that outcome would still be the case were grissom not actively sabotaging sara's efforts at advancement throughout the beginning of s4.
if he were to actually give her a fair shake and afford her some of the same opportunities he does nick (in terms of working high-profile solo cases and being given credit where credit is due for her accomplishments), would she eventually come out the clear-cut favorite?
of course, it goes without saying: one really has to wonder how sara would fare if anyone but grissom were the one in charge of making the recommendation for the promotion. would nick still get chosen if the evaluator weren't desperately trying to wrestle his burning love for the competition into submission? perhaps so but also perhaps not.
all of the above is to say that given the dearth of information we get on the topic, i don't think we can determine definitively one way or the other whether or not sara is deserving of the lead csi promotion in s4.
it really depends on what the job itself entails and how she actually performs in the areas related to those job responsibilities (removing any bias coming from grissom out of the equation).
as for the promotion sara gets in the series finale, she flat-out isn't qualified for it and in the real world never would have even been considered for it.
i talk about why not here, if you're interested.
thanks for the question! please feel welcome to send another any time.
