Nice topic. I'll take a shot at an answer.
Are the Packers a player or two away from being contenders? Maybe closer to 3 or 4, but without nit-picking I'd say yes:
-We saw what the offense accomplished with a pretty sub-standard OL. They're arguably one decent LT away from being almost 180 degrees the other way, o-line wise. And a good OL with the rest of that squad? Fuggeddaboutit.
-The defense picked up some crucial pieces in Matthews and Raji last year, and both panned out positively. There's questionable depth in the secondary (especially @ the safety position), but one can argue (and several have) that had Kampy stayed healthy and continued his transition to 3-4 OLB, the QB pressure that he and Matthews could have provided would have shielded the secondary a bit. So is it Kampy's return, someone new at OLB, or added quality and depth in the secondary that'll shore up the defense? You can argue for all of those possibilities, really.
-Ryan Grant is for real. But man, a change of pace would be nice. Not necessary, but that extra weapon could make the offense just unstoppable.
So yeah, they could add a couple-few pieces on the O-line, along the defensive front, in the secondary and in the offensive backfield, and that could put them over the top, easily.
Does Ted feel that way/will he go get those pieces? Man, I don't know. I will say that he sure did something to address the defense last year. Changing the scheme and coordinator, being aggressive in the draft to pick up Matthews, we all know the record. On the other hand, we've all been wringing our hands about the o-line for years and we're still worried about it now. I just don't know - but I do think there's hope - we did get Woodson, we did get Picket and Chillar and other pieces to the puzzle. He was aggressive last off-season. So it could definitely happen.
Now for the WHO. Here's my list, and I'll admit that it's not informed by, say, Rockmolder's excellent research or dfosterf's ridiculous financial acumen; it's purely my own ham-fisted attempt to patch the holes.
O-line - Realistically, I don't see any FA adds or some blue-chip draft pick, here. There just isn't much available in FA, and the crop in the draft isn't nearly as good as it has been in years past. BUT, there are guys like Gabe Carimi who'll be around in later rounds and could turn into another Clifton or Tauscher. Not the best outlook, but adding the right guy could straighten this line out.
Defensive front seven - FA-wise, the get here (if there is one) is Shawne Merriman. The knee should be in better shape the second season after surgery, and he's got a stake in rebuilding his image - we're also talking about attracting FAs to a clearly up-and-coming team, so it's not like he'd necessarily laugh at the idea. Draft-wise, there look to be several good possibilities, many that wouldn't require reaching to get. This can be fixed, and I think it will be. There will be more pressure brought to bear on opposing QBs next season.
Defensive backfield - I'm probably an idiot. I'll just go ahead and say it. But I like Mays a lot - I've heard the knocks, that he's another Roy Williams (who, by the way, was one HELL of a strong safety until years of hard play took their toll), etc. Williams didn't have (reportedly) 4.3 speed. I personally think this kid (and he is just a kid; it's not like he's reached his pinnacle of development, here) can be coached into one hell of a rover in the middle of the field. Will Percy want to catch that slant if he knows Mays is waiting to dismantle him? All that speed, all that size - I know people don't like the word 'potential' anymore (thank you, Vernon Gholston), but this kid's got it coming out the ears. Personally, I think he's gone by the 23rd pick, but if he's not and Thompson drafts him, you won't hear me complain - just like you didn't hear me complain about Matthews. Sure, we could have had a Michael Oher (though we wouldn't have the Ravens coaches or scheme, so I don't see that as being comparable), but the guy we got gave us a big bunch of our sacks last year.
RB - Several possibilities here - some are scary to me (these little dudes just seem like they'll end up getting crushed - I don't know that guys like Sproules come along very often), but there are certainly several good change-of-pace options coming out of the college ranks this year. This piece is one of the easier ones to get.
A lot of the above is unlikely - that's okay, it's early and we're still speculating. What's nice is that almost none of it is full-on impossible. It could happen, and considering that if it does we're talking about one loaded football team, that's cause for optimism, at least for now.
My apologies for an over-long response - I just really like the topic.