Miami's run differential suggests that they are easily much worse. Only Houston and Colorado are worse run prevention teams and their offense is nearly as bad as Washington's. I really don't think the Marlins are nearly as talented as people think.
Yeah but that's only a half-season sample size. I still think their offense has more potential than Philadelphia or Washington. Philadelphia's offense is basically riding on Carlos Ruiz right now and I don't think he'll keep it up for the whole season.
The Marlins' pitching isn't necessarily terrible; their run prevention problems are probably more defensive. Not that that makes them not count, however.
Doesn't matter if it's only half a season sample size in this case as they've got a -64 differential. That's obscenely ugly and one of the worst in the majors (only the Cubs, San Diego, and Minnesota are worse). They'e out performed their pythagorean by 6 games. This suggests that they will need increased performance just to tread water. Miami's offense may have more talent than Phillies (although Miami's talent is grossly overrated) but they're an 80 wRC+ team right now on offense (only the Cubs and Pirates are worse) which suggests that their bad offensive performance this year is pretty well earned (and this is with pretty good health). Philly by contrast is 13 with a 97. Yes it is based to an extent on fluky performance from Ruiz but that's not everything and they're far more injured than the Marlins suggesting their performance will improve when they get bodies back. As you guessed Miami are butchers in the field. The Indians, Rockies, Mets, and Tigers are much worse but Miami is still bottom five. Their pitching is indeed top half with a 7.8 WAR but that's not a particularly elite profile and there are multiple reasons to suggest that they will not maintain this based on ousized performance by certain players. Their bullpen is pretty weak so virtually all of their value is coming from their starters. In contrast Philly has an 8.7 WAR which is good for 9th in the Majors and that's with Halladay missing significant time. Their starter WAR is 3rd in the majors although their bullpen has performed even worse than Miami (not helped by Manuel's terrible use patterns).
The Phillies have been outscored slightly but if you look at their performance and their underlying indicators they look much better than the Marlins. Yes it's only half a season but that's a pretty good basis to establish quality trends and given Miami's relative health and the Phillies lack of it I do not see the Marlins as doing anything.
It's funny how I'm the engineer and you're the one that worships advanced statistics. But anyhow, despite what the stats say, I'm pretty sure the Marlins are better on offense than the Phillies. Giancarlo Stanton, Omar Infante, Hanley Ramirez, and Jose Reyes is a better core lineup than Carlos Ruiz, Jimmy Rollins, Shane Victorino, and Hunter Pence. The run differential is bad, but it looks less daunting when you consider the fact that almost the entire differential could be removed by ignoring seven games in June. Those are all losses, but I would bet if you removed their seven worst games and seven best games the differential would settle around more -20ish rather than -64.