Kicking a dead horse maybe, especially with a double post (which i dont feel would have improved the previous post as much as it would have made it too hard to read) but i had some more clarified thoughts as to a suggestion towards properly theming the gameplay of the mode.
I only mentioned it breifly but the propostion that farm tiles could be used as a fertile land indicator stands with the intent of having elves split between two different workshop building types, ones that are naturally derived and require this "check" as to assume that they are naturally grown and the more conventionally built types either to accomodate traders or vital workshops.
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Crafting Trees (noun) - Accepting reagent reactions to activate or after time disperse their own resources slowly nearby, the workshop built upon fertile land to mimic the implied function of vanilla DF elven forest retreat groves players can visit but not interact with in adventure mode
> Different kinds and sizes of groves - 'Arena' like groves that spawn multitudes of animals, with a greater input of reagents (see below) and being able to upgrade groves along different paths, pathing into more diverse natural creatures or allied supernatural ones like ents
- Sacrificial groves - Can spawn deer for a price as easy to hunt game to be released into the wild but in a inverse to the succubi hybrid demon den, the shrine will turn all surrounding non-intelligent animals into objects meant to represent physical embodyment of their souls, with (hopefully) a scripted size check to ensure the largest animals like elephants offer more powerful souls than badgers which are meagre and small.
- This might be helpful as to be a antithesis to how necromancers are meant to harvest souls from citizens, but necromancers use them for evil purposes and elves use them for... probably not evil purposes within context.
In all besides additional content to fill the gaps (such as any range of conventionally built and maintained workshops like advanced bowyers to respect their ability in marksmanship) it would help distinguish elves into a 'niche' and a archetype of the abstractly arcane, as the main races of the masterwork pack (excluding kobolds and succubi) play like each other industrialised to the norm of DF but leaning upon certain strengths of their philosophy and technology.
> Obviously if the player doesn't embark somewhere thats initially fertile on the surface such as a glacier, it is their own responsibility to either irrigate the ground or search for the caverns as a challenge which ties in nicely to the advised spots for elves to mingle without putting any caps on player's creativity to working around problems.
To conclude i would forsee elves as a defensive masterwork civ that relies upon spawners as a form of defensive buffer, and companions helping lead strong attacks in raids though its not outside the realm of possibility to obtain equipment for elves befitting their human like stature for them to lead the way as combatants by trade or invader drops either.