I wanted to throw some ideas out there, not being in the beta. I made a long thread about it earlier, but some ideas for techs would be based on the Master Quest victory condition. In other words, techs would benefit the player towards winning by the Master Quest condition. For example:
As stated above, perhaps unique Adventuring Champion abilities. For example, in Warfare, research high enough and get techs for abilities that increase stats, and whatnot. Research Magic, get abilities that boost mana regen, etc. Research Adventure, get techs for higher combat speed? Survivability? (Counter: stronger retaliation; Endurance: 1 health remaining from a killing blow), but special and Adventure tree unique abilities that help Champions become more useful, efficient, stronger, and faster, and last longer.
I imagine to complete the Master Quest, it would require high movement, strong/enduring champions, champions, dungeon delving. So perhaps, the techs in the Adventure tree could reflect that:
High movement: Techs to increase overland movement, allow movement into opponent's territory to access their dungeons (world Adventuring?), etc
Strong/Enduring Champions: Techs to give abilities, boosts to Champions
Champions: Techs to decrease cost and increase number of Champions under you (maybe through guilds?)
Dungeon Delving: Unique dungeons only the most foolhardy and brave adventurers would dare seek, with stronger monsters and more unique equips.
Briefly, the guild idea was to allow an pure Adventuring player to go without a city and survive, where since a player needs research points, perhaps they could build a guild on a library or whatever, or near one, and it generates research for the player. Furthermore, the guilds have a purpose in that if you bring a Champion to them, you can train them to get a unique Adventuring ability. For example, a Doctor's Guild or whatever you might be able to train to give a Champion, any Champion who trains there, for X turns and maybe some gildar, the ability of a regen aura or heal ability. Higher techs unlock more guilds and the longer a guild survives and generates Champions with abilities, the higher the prestige, which may lead to people defecting from opponent cities and very occasionally, generating a free Champion for you at that guild.