Personally, I'd really like to see more missions with a flavour of starting from a base, or that give the feeling of being a part of something larger, even if it may not make sense from the point of view of the campaign narrative in Arma 3 (like NATO invading Altis, or AAF retaking territory from CSAT, etc.).
I think we don't have a lot of missions set in Kavala and the surrounding areas, especially to the mountains in the South West.
For adversarial missions, I think one major problem we face is a smaller player count per team (even when 40+ people turn up), so we only really have 20 people per team. Doesn't leave a lot of people to do role-playing stuff like handle logistics and supplies, for example. Maybe something we could see more in coop, like Carson's Quds Radio Hour.
I'm also thinking of how submarines can be used, for some sort of stealth/infiltration missions. Such missions could also be asymmetrical PvP, and we do have a mission like that with the mine specialists.
I was also thinking of something like AI assisted PvP, where the teams are split equal but one or both teams get AI support. For example, imagine an AAF defence of Kavala. AAF consists of two squads + AI patrols and garrisons + loitering civies. There could be a player/AI driven AAA in the castle, and the hospital could be another key spot to defend.
Attackers can choose to attack from the sea, ask for CAS (AI planes or player helos), artillery (with restrictions on civilian targets), mortars, etc.
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There was some discussion in the Skype chat about giving COs a more non-linear experience, though that may require a base-driven approach. "Here are a bunch of vehicles to choose from, and here are your crew, where you choose to place them is up to you".
This could also lead the defenders to be more clueless about what will hit them - will they come by boat, submarine or helicopter? Etc.
Of course, this may lead to some issues with the ORBAT - Carson and Fer will aim their makarovs at me for doing that.
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FINALLY, and this is tangentially related, I'm wondering if there's any way to sort of make "modules" for F3 or FA missions (what I mean is, for internal use).
For example, if someone wants to nerd out over ambiance (like, I've been thinking of how Greek war songs should be playing from loudspeakers if we invaded Kavala), then they could quickly package it such that it would be easy to use by others in missions. Being self contained and consistent with the base game, these wouldn't be mods or addons that are needed player side.
I suppose I'm thinking of something like Wolf's function library but more "in-editor", or easy to do without knowing much of Arma's scripting. Drop a module, sync it to some stuff, set a few params and you're done.
I'm new to this stuff so it's likely already possible...