Again, this presumes JF can slug .500 as Doug suggested. If so, his power and the effect it has on the rest of the line-up will far out-produce the loss of defense. This team needs a power bat to protect Bruce IMO. We saw what happens last year when Bruce is trying to win games by himself with no one behind him. If JF can slug .500 it may fill the bill. I'm not sold that he really can, but that is the assumption here and I do believe he is more likely to do it than any in house candidate.
IMO, when a team has as many plus defenders playing next to each other as a Janish, Rolen, Dickerson, Stubbs group would have, those individual plus numbers that UZR or WAR indicate cannibalize each other. Many of those bloopers that Dickerson may get may have been necessary with EdE and Keppinger out there, but Rolen and Janish will catch many of them anyway making the reduced range in LF a lesser loss than the numbers may show. Similarly, Stubbs is going to get balls in the gap that previous CF like Griffey, Hairston, Freel, Hamilton and Bruce couldn't reach. Even Taveras speed is offset by his poor reads and is less capable of covering the gaps than Stubbs. A Neutral defender is really all that is needed IMO and the real loss in terms of outs is probably a lot less that the UZR scores of Dickerson versus another player may indicate. Somebody else is going to make many of those "plus" plays anyway.
As for Dickerson vs. Stubbs against RHP, I agree 100% that CD would be the starter in CF, but it won't happen IMO. This team needs a player who feast on RH Pitching. Phillips, Rolen, the catchers, Janish, Heisey and even Rosales hit lefties significantly better. Stubbs hasn't had big platoon splits, but Dickerson does and it would be enough for me to give him the nod ahead of Stubbs against RHP.