As much as Open Groups are a step forward in allowing us to feel more like a community that works together on its objectives (primarily RvR), they are still very flawed. If the idea is to enhance the feeling of community, perhaps segregating us into little 6-man groups (even if anyone can join) isn't the right idea. Wouldn't it better if we just got rid of the idea of "groups" entirely? Or reframe the party concept so that we are effectively grouped with EVERYONE in our Realm, always? Why can't we just see the nearest 6-, 12-, or however many people that are closest to us?
Since most of us feel that Open Groups were a great idea, why not take them to a whole "nother level." What could be more Open than the entire Realm?
To make it manageable as people filter in and out, maybe the UI would give us mechanisms to "pin" people of interest (friends, the main tank) up to the top. That would also allows us to keep track of someone who wasn't nearby. The idea of a party would still be useful, though it would simply provide a private chat channel and "pin" party members to the top of each other's lists. But instead of ONLY seeing their health bars and buffs, we'd still nearby Realm-mates filter up to the top, so we see who is in need of healing or other forms of assistance.
I don't envision this type of feature for healing alone. I would also prefer to see ALL other party-based mechanics, such as buffs, switched from having party-wide effects to having a proximity-based radius centered on the caster. In a game designed around "proximity-based grouping" (or Global Groups), people might generally communicate in the "global" /say channel; those nearby could get their text highlighted or tagged in such a way that they can be more readily identified and filtered to a special tab (to prevent channel spam.)
Another benefit I can imagine is better immersion. In the past, our characters sat still or soloed, with LFG flags or a LFM screen up, spamming global chat channels that spanned continents. Nowadays, we run up to whatever it is we want to do, stare at an LFG screen, and then join up (if there is room in the arbitrarily size-limited party or warband). In the future, I just want to run up to wherever it is I want to do, and we're automatically grouped. Done. Though, if I'm PVEing, I might talk in /say chat to see if I can tag along.
I realize this feature is probably not entirely feasible. All the checks to determine who is "nearby" could be taxing on the server-side CPUs; even though the client could do some of the work, such as sorting and filtering the list, much of it would have to be done server-side, to determine how much information to send to each client, and who is affected by whom's buffs. A Global Grouping concept would complicate other game mechanics such as combat where the XP and Renown reward factor the party system into account; without a party mechanic, you'd need to keep track of individual contribution on a much higher scale. If too many people "contribute" to killing a monster, then there should be no reward since its trivial. Only those individuals who contributed to killing that monster (so freeloaders who stand around the action don't benefit simply because they are grouped). If you change one game mechanic, every other game mechanic that depends on it is impacted as well, so this is just the tip of the iceberg of what would have to be changed in a hypothetical game that abandoned the traditional party concept.
But the advantage of removing the artificial party concept could be a more cohesive community that more readily works together towards its collective objectives.