They are horribly thought out and contain two mechanics that I found to be the dumbest thing I’ve seen in a game in a long time.
They can be annoying if you want to get the SP, I do wish they could be done with a split-screener and it would of been nice to have double the amount, or perhaps 8 offline missions, and then of course the freezes but... also I do think some were well thought out/designed, the Assault missions being one of my favorite single player missions in any game since that GRAW2 mission where the character is all beat up and has no cross-com, which I played many times over for fun. The excitement I got from the assault levels especially on AA, rival that one in terms of single-player satisfaction and I just think what is there is really fun and satisfying to me.