Natsu's forever been a tank who could withstand punches and kicks on end, and with Dragon Force he's only moreso. Punches and kicks aren't going to do much to his concentration, of all people.
Already been said earlier in this thread that Natsu's not one to resist the mind's failings anywhere
nearly as well as he can tank bodily hit well, something which I agree with.
We're not talking about power levels at all here, hax magic is what's being discussed.
WSD Sting held on only long enough for Rogue to tell him what to do. An interval stretching at what, 10 seconds at they very,
very most and of which WSD Sting was
mentally taxed enough to be rendered completely immobile against Larcade.
You're the one who brought up the possibility of Natsu transforming into Dragon Force.
I'm telling you that Larcade's magic won't let that transformation happen at all to begin with, let alone this sudden talk of yours about Natsu being able to maintain it.