I'm working again on Idea #1 (which, for future reference, will be graced with the title of-until further notice-of Our Worlds At War). There are three big concepts that I'm working on with it. These three concepts are tactical behaviors, experience control, and deformable battlefields.
Let's start with the first. Each unit has a type of tactical behavior, which is engaged by changing three sets of settings (or selecting a pre-defined "default" setting/macro). The first setting is Aggression-which can be set to one of three levels-aggressive (the unit will close to engage a target, getting as close as possible to use it's weapons), neutral (the unit will try to balance attack distance vs. range-trying to choose a range where it does as much damage as possible while at about half the unit's combat range), and cautious (the unit will try to keep a target at the maximum possible engagement range).
A second setting is vigor-how quickly a unit will engage a target. A unit can be hungry (where it will leap right off the bit and start following anything that it detects or targets), neutral (units will attack a target, or try to find a target within pre-determined norms-if it loses contact, it will try a short search, then stop), and full (units must be controlled to choose a target, and if they lose contact, they will stop and respond according to other rules).
The third and final rule is formation. We have a wide variety of formations, from lines to echelons to a circular formation. With these three choices, you have a wide variety of possible attack options. For example, a unit that is set for a neutral aggression, hungry vigor, and a circle formation will try to find a target, encircle it, and shoot it from every direction-with indirect fire units at various ranges with artillery and direct fire weapons trying to engage a target in a hull-down formation. Another set of units set for aggressive aggression, neutral vigor, and a echelon left formation will try to keep it's target on the left side, engaging them as close as humanly possible.
This set of rules will dictate a wide, wide range of reactions in units. And, it takes away a lot of the micro-management that quite a few games tend to indulge in.
A second factor, which relates to the first, is experience control. Call it "tactical intelligence" in games-if a unit encounters a unit that it has never seen before, it will engage in a sort of "poking" behavior, trying to make it do things such as attack, maneuver, escape, etc, etc. As it builds up a database of experience, it gets easier to engage and kill to hostile unit. Let's take an example-a group of human Strikers (tier 2 infantry) encounters a newly made Venusian Whisper (light, tier 1 recon vehicle). They will try to close with it, fire their weapons, and see how it responds. In game terms, the Strikers will not do as much damage, and will get closer than might be safe (Whispers have a secondary anti-infantry attack that only works at close range), etc, etc. However, as long as the fight continues, human units will learn how to engage the Whisper better-they won't get as close if they're infantry, armor will engage very well indeed...
And, this gets to our third factor-deformable battlefields. One thing that armor and infantry will do (our terrain is 3D), if they have defensive behaviors set, is to try and find a "hull down" position-where as little of their vehicle is showing to a potential target. But, if a weapon is powerful enough...it can shoot through dirt. Or sandbags. And, if you hit the ground with a powerful enough weapon, you can create a crater. Or your engineering unit can dig trenches and revetments for your equipment. There is a absolute "floor", but you can pretty much carve yourself all the way down to the bottom with enough explosives. Oh, and water flows into holes, too.
More ideas as my brain works on them.