So Die Hard on a spaceship? We did that with Starship Mine already but I definitely wouldn't mind seeing it again. Is Starfleet's version of the Hippocratic oath "First, do no harm, unless you have to, in which case go hard."?
As for the Crossfield-Class, I thought it might either be that the classification of Discovery made them change the format of it for obfuscation purposes. Either that or they built that ship from salvaged parts from the war, and the saucer/transponder was from a Crossfield, and Uhura was simply reading from the transponder code the ship class.
Congrats to our four new junior lieutenants, they did in 4 seasons what Harry Kim failed to do in 7.