floating crits isn't really a big deal to me, but it helps keep other people alive longer. Someone I know likes to field Stalkers, and I like to use LBX cannons on them. The result is always several critical hits that would destroy the gyro and damage the engine. Basically its a TKO in round 2 as the damn thing has issues before it gets into the fight with a good +10 heat being the norm.
the vehicle rules that reduces the crit and turning into a brick chances. Vehicle BV is overvalued due to the ease of critting one to death or turning it into a brick with a few pellets. The concentrated fire against locations due to fewer locations, backed by fewer internal points , and death once a location's internals are destroyed leaves vehicles as less then optimal choices for that BV. People tend to bring more vehicles when the rule is in effect versus standard TW and for good reason. Again, its about keeping people in game, but also to help diversify forces without some goofy RP nonsense.
Artillery, I shouldn't have to say that it is even an optional rule. It helps dislodge units and keeps people moving. People complain about how long a game takes, but when you have to keep moving or get hammered by my arty you might make decisions a bit faster then without. Also, you can die a lot faster, which reduces the unit count you need to worry about.
Mines, lrm delivered and so on, again it helps keep people moving since they don't want to get blocked off. It also helps the artillery. It helps those that have issues making decisions limit their possible options since they can't walk their assault mech through three 20 point mine fields without a decent risk, so its risk or go another way but that way.
Infantry rules, field guns and digging in above others.
VTOL strafing and bombing, chin turrets
Vehicles with sponson turrets.
Bracing
Sprinting great for light mechs
holding fire , bad for light mechs but requires some thought in most cases.