I didn't think it was all that. Quite 'by the numbers', overall.
Nothing (unless I missed something and, considering I didn't think any of the issues in Johns' run was 'all that', that's quite possible) established why Clark would suddenly reveal his secret to Jimmy.
Johns (through Clark) describing the nova-thing as 'thousands of times more powerful than [his] heat vision', yet only 'incinerating everything within a hundred yards'...meh. That's not...uh! Whatever.
The Time-Trapper-esque observer just, yeah, reminded me of the Time Trapper. Nothing more. Nothing, throughout his run, to give any indication as to who or what this person is, other than knowing the secret and having something against Clark.
The 'still doing the Superman-thing while powerless' was, for me, ruined with the 'how does Batman do it' rubbish. We know how Batman would have done it - we've seen it thousands of times and the HWSHE folk have it right: he would've thrown a batarang at 'im.
Anyway, the 'Superman-thing-while-powerless' merely reminded me of him going up against Mammoth back when he (Clark) actually was human, and the Wedding Album sans brick and scraped knuckles. Johns also handled it better back in the Legion-arc.
I was never keen on Johns taking on the writing chores - I've always found him either writing around Superman (Royal Flush Gang), depowering him (Legion-arc), or setting up an/some idea(s) and not following through (New Krypton).