Reading through most of these reviews the praise for the game so centered almost entirely around gameplay mechanics with the remainder of the game getting a underwhelming token of approval. When I look at a BioWare game I don't want to hear how the actual story of the game is uninspired or a standard affair. BioWare should be Story focused and the lack of enthusiasm surrounding the story and characters comes across in a LOT of these reviews not just the one I quoted.
Tbh, for a loot'n'shoot game, good gameplay is a lot more important than the story that you go through, especially since it seems that you only need one character and the other mechs are basically leveled loadouts. The most important bits about the story will be the little window dressings you get at max level while hunting for more power.
Though I understand being disappointed if you were expecting something different.