Why? Is this an aesthetic goal or do you just have a thing about controls?
Just about any head that's capable of decent tone is capable of plug-and-play. Just dial in the amp's gain, volume, and eq until you like the sound, and then leave the controls there.
In practice, eq and gain controls are handy tools. Your tone from night to night will seem altered by stage design, your amp placement, Fletcher-Munson effects, frequency masking from the way your bandmates have dialed in their gear, PA spill, etc. Even if your rig is only for stage monitoring, it's sometimes a gig-saver to be able to dial in some extra mid-range intelligibility, dial out some low-end mud, or just adjust to the apparent boost in bass when you play at higher volumes..
You are correct.
The whole point of all those pesky knobs is not just to adjust to a particular tone (which you can do with your hands if you want) but to adjust to the room and the stage. That's why they are there.
