TL;DR: I've already 'cheated' a lot to help the group survive the first mission, and it seems like I'll have to cheat even more if they'll make it to the Keep. Did I do something wrong? What can I do ...
If I give an enemy NPC a Meltagun in combat, nothing prevents the players from taking the weapon after they kill him, which leads to the inevitable snowballing: they get stronger, I need stronger ...
I've been a DM for a while for 3.5. I've run many NPC characters, however only a small fraction of monsters out of the books (comparatively). Also, I like to use templates liberally as well as advance ...