In most cases, the battalion that you're running for will already speak on the application expressing their opinions.
Now here's the thing, giving the battalion the final say will cause some issues with some player(s) leaving a mark on their heads.
Let's say I am the 501st XO, a Colonel is currently running for the position but I do not think he or she is doing well enough to get this position, so this XO expresses his opinion to the others in the battalion and that alters the final decision leaving the Directors no choice but to deny the application. Also, this will remove some powers the Directors, Palpatine, Marshal Commanders, etc will have on this decision making progress. If all these people agreed on having this person be Rex, but the 501st isn't for it they shouldn't be denied the position; that's a bit silly. This leaves too much power on the battalion and could result in them never having a BCMD at one point.
I do believe the battalion that you go for should overall like you and think you're a good leader, but I feel that isn't needed.
Now here's the case with the second option, in some battalions it is already like that, and putting restrictions on how battalions run their own hierarchy would kind of skull fuck their freedom. The previous BCMD should've already chosen someone they believe deserve this position, but in some cases maybe that person just isn't right for the whole deal right? Maybe some Colonel would be a better leader and the XO is more of a follower. Again, this would completely eliminate interviews for positions and would most likely result in someone getting the position that they don't deserve.
I am going to drop an example that might never happen, but who fucking knows.
I am Rex, I choose my best friend that just joined the battalion to become my XO because I know I'll be leaving soon and I want my friend in power just in case I come back.
Again, this might not ever happen, but why leave it to chance?
I am confident in what we have now is sufficient enough and we should keep it that way.
TLDR; no -1
i am aware i get sidetracked often so if you're reading this and was like wtf is happening thats why.