- Aiming for the legs means using that inspired ability, or knocking them down, correct?
Yes. If the mech is standing up you need to use your inspiration but if it's on its back every attack you take on it will be aimed. To knock them down you can either:
Destroy one leg - This will make it fall down and remain down till it's next turn. Can only be done with the inspiration ability;
Do enough stability damage (bottom yellow bar) - After that bar is filled the mech will fall. It's a more laborious job but effective if you use weapons with high stability damage (LRM, SRM, shorter-range ballistics, etc).
The reason aiming for the legs is so important is that if done corretly you'll get a free mech after the fight (you'll manage to scavange 3 parts). If you kill the mech any other way, besides headshotting the pilot but that's ultra rare, you'll only be able to scavange 1 or 2 parts. So the best and fastest way to increase your team's power is to be meticulous on the battlefield. Bear in mind the inspiration gain per turn is tied to your morale so as the game progresses you'll have an easier time using inspiration abilities.
- What's the advantage that scanning before they get LoS provides and/or denies them?
Basically you can only attack what you can see. This is true for both you and your enemies. So if you can scan them from far away with a scout you'll be able to attack them with long range weapons and possibly destroy the mech before it comes close and provides LoS for his team to do the same. Earlier in the game these scouts will be light mechs so the tag & kill in a single turn is easy to do.
- How do you tell what actually does good damage and all? I get the feeling the damage numbers aren't really telling the whole story, and some things like lasers feel woefully underpowered... But then again the visual feedback may be misleading, and damage effects are only applied at the end of the attacking round, which means the weapon getting that gratifying kaboom isn't the one that necessarily did the most damage. I still get the feeling AC is the most powerful thing so far. Aaand your comment at the end kind of confirms it haha.
It's a tough question to answer because there's no real answer. Every weapon has it's uses and can be mix & matched with others depending on what you need your team, and individual mech, to do.
First things first, there's 2 types of damage: Direct damage done to armor and core and stability damage that can make a mech fall down, lose accuracy or lose movement range. Every weapon does direct damage but some also do decent stability damage. For instance a M Laser does 25 direct and 0 stability, meaning it's a decent weapon to kill the core or strip the armor but won't help at all if you're trying to make it fall down. Looking at the rockets, LRM5 for instance, you do 4 direct and 2 stability per rocket (multiply by 5 rockets and you get 20 direct and 10 stability if you hit all).
Then we need to remember that there isn't a single Armor/HP bar on each mech, each part has it's own. So if you fire 5 lasers, each dealing 25 damage, at best you'll deal 125 damage to a single part, at worst you'll deal 25 damage to 5 different parts. The first option might do heavy damage, the second is barely a scratch. This is the reason you'll never want to use rockets to deal damage, just to destabilize.
Ballistics are a well rounded option that I liked to use on all my mechs but beware because they are very heavy and are ammo dependent (makes the even heavier).
- Facing sideways is actually surprising, I assume you want to alternate, lest you loose all armor on that side and Bad Things start happening?
The idea is alternate between sides yeah. This way you'll double your effective Armour/HP at the risk of losing an arm and all the weapons and mods you might have in it. Still a better option than opening your torso to a direct hit and losing the pilot and the mech for the fight.
- Long range rockets, meaning LRMs?
Correct. There's also the short range variant (SRM).
- PPCs, how do you feel about those?
I liked them a lot. One of my late-game mechs had an AC/10 and 2 PPCs (one with +direct damage and another one with +stability damage). High range, high damage killing machines that produce an insane amount of heat. Earlier in the game, if you decide to use them, be sure to not to use them every turn otherwise you'll risk internal damage and a shutdown. Later you'll find better equipment and skills that'll allow you to better deal with heat.
Enjoy the game
Here's hoping we'll eventually get a sequel someday...
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