I think Nathan has always been about gaining power and being in power.
Nathan already progressed beyond that in S1. Now he's regressing. Characters should always move forward in their arcs.
Here's how the same ends could have been achieved so much better: if Nathan had done nothing while the battle between Arthur and Angela escalated, not wanting to be disloyal to either parent. The tension ratchets up over several episodes and then something catastrophic happens.
Say Tracey isn't a scheming bitch but rather a decent person, and is killed because of the fight. Or another catastophe, but it has to be something that smacks Nathan in the face and makes him realize that having people with powers running around loose is simply going to keep generating catstrophes, because stupid humans cannot handle this much power, and it forces him to rat everyone out to Pres. Worf.
We've got to
see the process whereby this basically decent guy, which is what he's been since S1, is forced to do something questionable, but is the best he can make of a bad situation. The process is where the drama becomes real, and this season we haven't been seeing many processes. We get events that occur, like Peter getting the hunger, but there's no process that he goes through, no resolution, and ultimately no point.
The supersoldiers plotline was unnecessary and went nowhere anyway. The guys didn't even have one battle! I was expecting
something.
from season 1 onwards, has been that some of these guys are dangerous and they should be restricted somehow. First he tried to expose them, got shot, then he tried to fight them, got beat, then he tried to create a counter army, got nowhere, so now he's exposing them to the government.
The logic of that process was interrupted by the supersolider plotline, which doesn't fit the pattern, since he's giving people more powers rather than restricting them. If Nathan were following his own logic, he'd realize that the stupid humans he was giving artificial powers to would go off the reservation very quickly. That's why people having powers is bad - they can't be trusted, so why should his Marines be any different? Ironically, ratting them all out to the government is probably the smartest thing he's done so far.