1) What's the right scale/force size? I played Skirmish Sankin at squad size earlier, and Chain of Command at platoon sized. What I really want is full combined arms, and for that you probably need at least a Battalion Group, which is what I'm playing here. SS worked pretty well, but I think CoC was stuck between being a real skirmish and proper combined arms, and felt a bit too "gamey" for me. With the latest version of Contact:Wait Out I've upped it from a Coy Gp set to a Bn Gp set, and its closer but I think the sheer variety of arms in a combined arms game can rapidly make it too bitty (not complex, just bitty as every weapons system is different). Perhaps next I'll try a "simpler" set of rules, perhaps Cold War Commander which seems to get good reviews.
2) Indirect Fire. It does seem that on most battlefields for the last 60+ yrs that indirect fire rules. You come under fire , your weapons can't kill a well protected enemy, so you bring in the fire support, from 25pdrs to Apaches and A10 - not much or a wargame. You can postulate a scenario where IDF is not available, but then you really are back to the very small scale and it's all about use of cover so has to be platoon or less.