I have to agree that while some missions can be things I don't feel like doing at the time, I pretty much avoid Meteor Storm missions if I can, they just take too long. So often I feel like I'm just standing on top of one stack of boxes, waiting for the rest of the damn rocks to fall.
Rather than focus on monsters or defending robot blasters, I think I'd almost rather see this whole mode re-imagined as a more pressure-based scenario. I'm picturing instead of 100 small meteors, you just have to fend off like 1 to 5 huge ones. In this scenario, you have to keep shooting the rock to whittle down it's monstrous HP, and to push it back up. If you don't push it back, it crushes you and all your supplies. Meanwhile, monsters keep coming in. So now, it's a blend and the player has to make strategic choices. Do I fight off monsters, or do I shoot the rock a few dozen times to push it back up and buy myself a little more time?
The current form almost has this mode going on, but the rocks move so fast and hurt so much that they're always the top priority. And there's just so damn many of them and it takes so long to finish.