Wi-Fi Direct is nothing more than running (e.g., 802.11n) software AP with WPS on one device ("Group Owner") and having (multiple) peers connect to it to form a "group" -- it's just a normal AP, you can even connect legacy Wi-Fi devices to it. It does add functionality to automatically negotiate which device becomes the access point and to do some service discovery on the link layer before connecting.
The problem with WiFi Direct is that all its local mobile-to-mobile capabilities are disabled if the group doesn't have a node connected to a tower at all times. For example, you can't have three devices up in the mountains exchange files or messages, unless one of them can get the OK from a service provider's tower. WiFi Direct stops as soon as you lose cellular signal or experience a service timeout. It's crippled by design.
EasyMesh doesn't seem to offer any neighbor-to-neighbor utility; It appears to be focused solely on expanding coverage of single-point-of-control networks which are already overcrowded (hence the need for so many range extenders). When are we not in range of half a dozen or more WiFi networks?
I see adding more APs as an exercise in futility. The primary issue is overcrowding, not signal strength. Remove all the other nearby networks & one router easily reaches across most buildings.
Sorry, I guess that's two topics in one comment, but I'll repeat my primary question: In what way are these different approaches "completely" different? They seem to all be chasing roughly the same goal. I also feel that "mesh" has stagnated due to lack of hardware support (& accompanying lack of open source firmware).
I'M SORRY! I was thinking of LTE Direct, which is crippled by design. Please disregard my statement about "WiFi Direct" needing a cellular tower.
Bluetooth profiles, and vendors restricting their devices to sport only certain profiles, are a good thing for compatibility, since it ensures (if done correctly) that devices (i.e. applications in fact) from different vendors can talk to each other.
"WiFi direct" is yet another completely different thing, that is meant for peer-to-peer connections (note: two communication partners) without needing an AP, which 802.11 consumer standards (b,g,n,ac) all did and do otherwise.
Also this standard has nothing to to with flash-mob gaming, and won't allow for it. This is AFAIK meant as a standardization of several so far vendor-specific efforts to extend networks through the use of several APs (similarly to how repeaters were used). Still a good thing, because it is no longer vendor-specific if my devices support the standard.
By expecting mesh networking to solve your applications needs you are IMO skipping a few layers in between. You want ad-hoc, high throughput mesh networks, stateless auto-configuration, service discovery, and quite a few other things regarding routing, QoS and flow management as well as connection management (reliability, multicast?)...
This is not the standard you are looking for. For now you would need to look for solutions in the application layer IMO.