As a Cubs fan, I don't want to see Wood close. They signed Dempster to a contract for that purpose. 2 seasons ago he had the best save rate in the majors. Last season sucked, but the Cubs couldn't win, so he wasn't getting regular work. So far this year he looks great, so there is no reason to look to someone else. The only way Wood gets the job is if he comes back puts up great numbers for a month, and Dempster blows a handful of saves in a row.
I have no doubt that Wood can be an effective reliever when healthy (although they have said that he took a long time to warm up as a starter, so I don't know how that will work out for him as a reliever). But I don't want him to take over the job, get hurt a couple weeks later, and Dempster has to come back and get in the closer mentality again.
If Dempster can't get the job done, we have Howry and Weurtz (and possible COTF Cherry), so why throw a guy in the spot that's going to get injured after a few appearances when your healthy guys can get some reps in at closer and be that much more effective at the end of the year (when Wood will most likely be back on the DL - if he ever makes it off).