Well, in Dr. Who, the real main character is the TARDIS; so in any follow on Trek, the main character could be the starship.
Honestly though; I’ve thought something along these lines should have been employed long ago with many military style shows. People transfer, they retire, they enlist, they receive commissions, and sometimes they die or get wounded.
If they launched a new show, they could easily sign actors and actresses up for half season, full season, two season, and three season contracts; with the bulk being the half season. The reduced amount of time each would be signed up for, should drive the costs down, and with the prospect of only being around for half a season, shouldn’t type cast to many actors/actresses into their roles.
Then, as the show progresses, characters could come and go; the audience would never know if the person is going to stick around, or is going to get transferred/killed off.
The impact of a red shirt dying, after you’ve seen them in three or four episodes would be much more devastating, and add a since of realism to the show, few have seen before.
It would be awesome, to have the XO beam down, three or four times with Ensign Charlie Smith; then mid season, after having seen Ensign Smith a few times, having developed some interaction with him; suddenly he dies. Or, Lt JG Jones, in Engineering; being transferred after two seasons.
In many ways, this is exactly what DS9 did with Worf and Obrien; bringing them over from TNG; and developing new stories.