Unfortunately, I think most folks would have been perfectly fine with HL3 being a continuation of HL2, myself included, so now we have to wait for Valves hubris to subside.
What could it look like instead? Anything! I think a Divinity-style RPG Half-Life would be heaps of fun. Or a hero-based RTS that still has Gordon Freeman centre stage. I think basically any genre that can tell a story would be fine.
Of course this guarantees disappointing a lot of people, but I feel there's a lot better chance of Valve producing something creatively worthwhile this way than trying to make a "vastly better Half-Life 2", which is what most people seem to be waiting for.
The guild was great at identifying issues to work on, but most members didn’t have the time to actually contribute on any of the more hairy issues. It was basically group therapy.
Also - and perhaps this is just me - but the world “guild” just makes me think of Dwarves and fantasy games. “The dwarvish guild is requesting more iron ore to make hammers”. Hard to get taken seriously.
Guild is not a term in corporate parlance. Perhaps “think tank” resonates a little better? IDK
From what I see and hear in this industry, that's not uncommon to have that much 'free' time anyway.
The company produces several distinct but related products. All of the products have a shared set of concerns and resources. They are all built upon the same in-house operating system, they all use the same development and testing lab infrastructure, they all have UIs, automated testing, etc. Migration of CIs between teams (generally voluntary) is relatively common.
To avoid duplication of work and to coordinate work and improvements on these shared resources, "guilds" spontaneously formed. Guild members more or less represent their own team's interests while also contributing to guild efforts as a whole, if they can, and when they have the time. Each guild has semi-regular meetings. There is usually a guild "leader" but this person is more of a secretary in the sense that they only schedule meetings, take notes, and facilitate communication. Guild leaders are just CIs like everyone else in the guild and have no actual authority to direct work.
Company management is aware of guilds and will allocate resources to them if specifically requested but otherwise have no involvement in the guilds and never attend meetings. Guilds (along with non-asshat managers) are one of the things this company has that I wish was more commonplace in tech companies.