This is the game I've been waiting years for since MW4. The video showcasing how scout mechs spot for LRM capable assault mechs is great.
Indeed, the system seems to be working.
Some thoughts on strategy:
Basic strategy:
When the round begins, scout mechs engange and tag targets (preferrably enemy mediums and heavier though bombarding enemy scouts to pieces right away might be a good idea if possible), allowing artillery to start pounding them. Some of the scouts harrass enemy scouts.
Mediums arrive soon after and start holding the line until the heavier elements arrive. Some of the mediums (fast, a lot of guns, light armor) start hunting (with your scouts) enemy scouts and hunter/harasser mechs.
Heavies and assault mechs keep the line. Assault mechs tank, faster heavies (less emphasis on armor) try to to push onward but should avoid pushing the other team back to their base, instead the battle should be directed to elsewhere, this allows a strike group to march directly to enemy base.
As for what makes a good strike group... intuition says: balance. Heavies mostly, with fairly even armor, firepower and speed. Possibly a lance of 4 heavies, with three of them focusing on one thing each and the fourth being a balanced one.
Defenders should be fast, reactionary group which mostly harrasses the main battle line mechs but can easily retreate back to base to defend. Defenders need staying power, mostly energy weapons but not many of them to free weight for other things: enough speed to move quickly and enough armor to stay up.
Personally i don't think assault mechs would make good defenders, they're way too slow to react to things. Turret configs are too easily destroyed or avoided.
Fast assault mechs are not a good idea, assault mech engines are too inefficient (the lighter the mech, the more speed it gains per engine upgrade, no?).
I'm just guessing here though. And naturally map affects a lot on these, i think it is unlikely for a city map to have a line of battle, ambushes and duels are more likely.
EDIT as for MW4, been playing it, Black Knight and Mercenaries for a few days. And now the game decided to ignore my main mouse button, ie i cannot fire weapon group one or do anything else with it (other than click menu buttons). Really odd issue, worked fine a few days ago.