Of course level 1 is when one mans army should start. That is obvious and it will surely be like that. I assume that Larian want us to try other combinations that is all.
Level 4 is when in is all over in this game at the moment. It is exactly the same as making it to Crystal village in the last one. It is all too simple after that - you made it there you will not die.
It is tough in this game to get to level 4 (without cheating by running away or using the boring sneak/snipe/sneak tactic) and there are reasons you may not want to (try to kill Dallis for example).
I'd not be adverse to lone-wolf starting earlier (although you can just play on easy if you want) but what you shouldn't be able to do is abuse an earlier advantage. I don't know if you noticed but previously if you picked up a companion they had the same XP as you. Now they do not - they have the XP from the basic quests (I think).
I picked up Louise (or whatever her name is) to teleport one of my characters back from where they were stuck when I was at level 6 and she was 7600 XP and a whole level behind me for not doing the optional quests...
Really lone wolf / One mans army should be a choice that sticks. At the moment it is just a placeholder as although you can get to level 8 before the last fight there isn't really anyone left to test it on. If you are on level 8 already the last fight is trivial - you just walk in the front door.
In my current play through therefore (as I'm weak) I killed the other 4 (so I can't come back and recruit them) and made a pact to sell every weapon that was not a staff (so I don't cheat by using a bow).
Now if I didn't have to save/reload after every move I'd be happy. Missing 100% of the time is a bit rubbish for an ex-blind lone-wolf but I digress
