Oh yeah, 6mm skirmish is actually my preferred scale. I'm impressed that you could derive that from this rule-set.
To be honest this is meant to be fairly 'tinkertoy'/setting/miniature agnostic, so the exclusion of theming is a conscious choice, not just trying to save space. There are no units, one to save on space, but also to force players to make their own. I want people to be able to use literally any minis. If I had to pick a setting, think of a sci-fi version of the wars in Zaire/The Democratic Republic of the Congo. Unfortunately that's quite a bit dark 'fantasy' (Note that the wizard is invoking orbital weapons). I feel like given the limited space the rules are working with I do a fairly okay job of creating an (optional) implied setting if that's desired. That said you're not the first to raise that point, so if I do more work with this, I suppose I should add more on that front. And yeah I'm familiar with sludge, but haven't gotten around to buying the ruleset. Not convinced it's better than Turnip28 anyhow.
I seem to have explained the whole activation process a bit poorly, as what you're describing is actually fairly close to the intended function.
"Each Unit may take a single action when activated, and after taking an action may Roll against their own Elan for an additional action, so long as their Elan is above 1."
The intended meaning is that each unit gets a 'free' action once activated. After acting, a unit may roll for an additional action, and they can do this so long as they have an Elan higher than 1 (Since making that roll would kill the unit).
Roll less than or equal to the Unit's Elan to take an additional action. If you Roll higher than the Unit's Elan, their activation ends. Either way, after rolling reduce the Unit’s Elan by 1.
Taken together, this is intended to make the decision to 'push' for additional actions an actual decision, with the additional action not a sinecure, but something that you might not get, while the cost is always going to come up. At the same time, because the first action a unit gets on their Activation doesn't require a roll, it does not deplete their Elan.
A Unit's activation may be voluntarily ended by their player at any time. Elan goes up by 1 up to the Unit’s starting value at the end of a Unit's activation.
This is meant to make it clear that rolling for additional actions is not required, and allows a Unit to 'regenerate' Elan, by only taking the 'free' action that does not require a roll. This removes the need for a 'rest' action, and allows for Elan to regenerate passively throughout the game. Do note that any attacks against a unit it survives will also reduce Elan, so Unit effectiveness should continually degrade, forcing a relatively quick resolution of the game.
If you have suggestions for how the above can be made clearer and more effectively communicated, I'd welcome them, as clearly I've already failed on that front once.
The restriction on the Wizard power being a one shot is so I can borrow existing mechanics, which A) The whole purity of design/design by subtraction thing, and B) Let's me save space. In an expanded game, there's clearly a ton that can be done with powers like this I agree.
Side note: We're both wrong, technically it's "élan", not elam or elan. Broadly it's a stolen french word meaning eagerness to charge to the sound of the guns, seen often in discussion of Napoleonic armies.