I think there has been some sloppy writing, though not in some of the specific examples you cite. I think the book is still better than it has been in a while in terms of pacing and art.
Dr. Fate made sense in the context of the story and it was explained. It wasn't Flash just going for someone with power BUT for someone whose name had a reputation. Sure, Thunder is as powerful and a known entity, but he's not going to make the villains pause as someone that is apparently Dr. Fate. HOWEVER, where the writing was sloppy was that this was not set up at all. There's no mention that the Flash knows there's a new Dr. Fate or even where to find him. There should have been some discussion in the previous issue about Fate that set it all up.
Likewise, there's no set-up of the villains, who they all are or their powers. There's a new Eclipso? And, he's scared of Dr. Fate? Eclipso has been a cosmic level baddy himself of late, needs more explanation of who he is and why he's there. Sure, the supervillains as a group took on most of the JSA, but that was with the element of surprise. With them fractured and in retreat, again it makes sense that the heroes could get the drop on them.
What got me was that there was an actual argument instead of just going ahead and splitting the team with the injured getting back to the Brownstone and those able to fight to track and take down some of the straggler villains. Or just have Flash to follow the villains unseen to get more info of what was going on? Or Wildcat or Dr. Mid-Nite, playing up their dark costumes and pulpish angles, which would have been interesting angles as opposed to their one-note personalities of bruiser and doctor.
But, you are right in that Magog's speech is out of character, especially for a MARINE, one of their motto's being "no man left behind", something exploited by the enemy in Vietnam.
Ed - you missed my point about Dr. Fate vs. Jakeem and the Thunderbolt. Why go to the trouble of getting someone the villians might THINK could do something to them when you could get someone who actually COULD do something to them? What's more, it would have taken less effort to get the known quantity. If Jakeem is supposed to be unavailable or something, that's fine but mention this in the context of the story. Ignoring it is sloppy writing.