Hey Dan, I own the older model and have had it for some time now and really like the thing. I haven't seen the new model in person but a member here bought one of the new ones and I asked him to post some pictures of the inside, which he did. From what I can tell - based on his pictures - there doesn't appear to be any major difference with the water pan/wood box/burner configuration. As for the grease deflector, I didn't notice that on his pictures. Is the deflector on the door?
As for any mods, I think the mods required for the older model would still be required for the new model, including the rope gasket around both doors and pitching the factor thermo that comes with the MF and either installing a decent/reliable analog in the door or going with a digital/wireless unit.
As for the benefit of the new side-shelf, I don't see a major gain here, when comparing the price difference. Plus the shelf is on the hinge side of the smoker, so when ever you open the smoker door, the shelf will be blocked... just an observation.
As for the price difference, I just don't see the newer model being worth the extra cash but that's MVHO.