Well let's first see what arguably the Nats biggest starting lineup weaknesses are, from biggest to smallest.
AVG: Usually you ignore average, but when it comes to the bench it matters. Sometimes a walk isn't good enough. Sometimes you need that hit. The Nats regular lineup was pretty terrible at doing that simple task. Morse, even with a slight slip, Zimmerman, and maybe Ramos can get a hit. I wouldn't bet on anyone else
isoSLG: Other times you need more than just a hit, you need a home run. As a team the Nats were mediocre at hitting the long ball. Individually, Morse was the only one who was great at it but you have to worry about him keeping up a top 10 in the league level. The next best guy on the team just to get the big hit was Nix, who is gone now. Zimmerman being healthy could pick this up, and Espinosa and Ramos aren't bad, but really LaRoche is the key here. He was a decent power threat if he was anything but I'm not sure I want to bet on someone coming back from injury hitting for power especially one hitting so feebly before going out.
OF defense: It all depends on the lineup. If it were Bernadina-Ankiel-Werth , maybe you can live with that, but that seems an unlikely starting group. Something like Morse-Bernadina-Werth is far more likely, but it's also asking for trouble defensively. With Morse seemingly set in left and CF maybe manned by Werth (who is aging and had an offyear as a corner OF last year), or Bryce (who no one really likes as a CF, but he may be not terrible enough to start) having a great OF defensive player is that much more important.
OBP: Again pretty mediocre. Outside of Werth no one could take a walk, but Morse, Zimmerman and Ramos hit well enough that they are decent bets to get on. It's a little better bet that whoever is up for the Nats can get on base than can get a hit or slug a homer, in my mind.
Handedness : The Nats lineup is righty heavy. Espinosa switch-hits but is better from the right side and Ankiel lost the split advantage last year. LaRoche will help, but a lefty bat on the bench is still a need.
MI/3B defense: This is the inflection point. Everything above here is definitely a weakness (sorry - but the offense could be kinda bad this year), everything below this I'd consider a strength or at least something not to worry about. This one itself is a bit tricky. Zimmerman had an off year, and Desmond has his issues, but fielding stats can be fickle. I trust that these guys can hold it down. Then again that's two years now where Desmond hasn't become that great fielder the Nats think he should be. There probably is worth in carrying a slick-fielding SS.
Speed: Not too bad. Werth, Espinosa, and Desmond are good baserunners and no starter last year was a big liability. That won't be the case this year as LaRoche is a plodder, and post-injury Zimmerman will be a touch slower. Still, a pinch runner isn't so big a need that you can't let it get filled as a side product of filling something else above (like OF defense)
1B defense: LaRoche is pretty good. We'll see if that stays true but this is only an area of need if your first baseman is terrible defensively. LaRoche isn't.
C defense: Ramos is very good defensively. The back-up need not be.
OK now let's see what the current bench bring to the table. Let's assume Flores, Bernadina, DeRosa, Teahen, and Cameron for now, and look at Lombardozzi.
- Flores has to be there. He might be a bat with decent pop. Hard to tell.
- Bernadina can give you speed, and play corner OF well. He also bats left.
- DeRosa is not really good at anything - maybe give you decent corner OF D? You can't say get on base given what he did in '09 and '10.
- Teahen is even worse - let's hope he doesn't break with the team. He does bat left. I can't deny that.
- Cameron probably can still play CF well. Offensively a black hole though.
- Lombardozzi by all accounts is a good 3B/MI fielder. I'll trust that, but the minor league stats say he's a singly Joe, and one that hasn't shown up in the majors yet. Switch hits and not a bad baserunner.
Ugh. Well as you can see the Nats bench does nothing to address the biggest weaknesses in the Nats lineup. There are no guys good at getting a hit, no one good at hitting the home run, and no one good at getting on base. Right now you'd have to hope Flores starts showing one of those skills, or maybe Lombardozzi starts rapping a few singles. Defensively though things look ok if Lombardozzi and Cameron are on the squad. Honestly though, beyond Flores, the only guy I feel the Nats need to keep on the bench is Bernadina. While you all know I don't like him as a starter at all, he makes a very nice bench guy for this team.
Is there anyone out there that can help the Nats? Probably no one that will take a bench role rather than retire. I think Derrek Lee could help with pop, and JD Drew has always had a good eye, but I imagine both will go home rather than ride the pine for the Nats. Ibanez could bring a lot, if you think 2011 was fluky, but most believe he's completely done. Vlad Guerrero or Magglio Ordonez could be decent "just a hit" guys but that's all they would bring and they are looking at AL teams for one last chance to DH. Aaron Miles is probably the most interesting guy the Nats could get. He can get a hit and bats lefty. Maybe Jason Varitek as a slug only guy? But neither of these to is anything to get excited about.
Truth is it's hard to get guys that are good, even at one thing, for your bench because if you are good enough at that one thing, some team will likely find a spot-starting role for you. You have to move fast, take a chance or two and get a bit lucky. The Nats moved slowly on putting together a bench looking at character as much as skill. Hopefully that won't cost them when they need a bit hit down the road.