Does the god subtype bring with it any special connotations or abilities, or is it just a fanciful descriptor with no real benefits?
I don't have the book yet, but I'm certain it's fanciful; all descriptors and subtypes have been thus far, except for where they interact with the occasional magic item or ability. As I pointed out above, they are quite inconsistent, as well. For example, Drow in Monster Manual 1 don't even have the "drow" subtype -- they're just "Medium fey humanoids". For what little it's worth, this line in the statblocks of monster in Keep on the Shadowfell is sometimes totally different from the one in the statblock of the same monster in the Monster Manual, although that might just be a change in design philosophy. (KotS used a lot more subtypes, IIRC.)
As I'm looking over the first two Monster Manuals, I'm noticing that subtypes are usually found on creatures whose name doesn't indicate their nature. For example, Duergar have the "dwarf" subtype, but Dwarves don't. Most Eladrin don't have the "eladrin" subtype, but the Coure of Mischief and Strife does (on the page right next to an eladrin without the subtype, no less). However, most goblins don't have the goblin subtype,
including the Lolthbound Goblin -- but
not including the Lolthbound Goblin Slave on the same page in MM2. Go figure.
Given the lack of significant mechanical effect, I'm going to chalk these inconsistencies up to their insignificance. It's not cool, but at least it doesn't wreck anything.
Most, if not all, deities to this point have been immune to attacks by characters less than 20th level. So maybe the "god" keyword has that as an implicit feature? Still, I thought that was something they were trying to avoid -- monster features that don't appear in the statblock.
I'm with Runestar; they may have just stopped bothering to print that bit, because of the extreme unlikelihood of any 19th level characters ever being a threat to a creature with these stats. However, if it ever came up in game, I'd still apply the "20+" rule anyway, because I know it. Also, can anyone even confirm that this sidebar actually doesn't appear in the book? We know the excerpt wasn't complete...
I'm still inclined to believe that there's nothing to this "(god)" subtype bit, except for what we're already familiar with. I just would've preferred the word "(deity)", like they've used before.