I have a feeling it won't be too much different from the last two.
When you get down to it, it will be nothing but diving behind cover and the characters cursing at either their allies or the enemies, the rookie dying, some characters that are close to the main characters will die and the emotional connection will be lost because up to that point all it was was cussing and shooting. Cole yelling "WOO!" "COLE TRAIN BABY!", Baird whining, Dom being an emo, and Fenix being emotionless.
Seeing as they're making Anya playable I have the sneaking suspicion female locusts will also exist. *gag*
The least I can hope for is a final boss worthy enough to be called final boss.