I think it’s more of a personal preference if legacy was more fun or not.
Before the mythical weapons were introduced weapons ranks didn’t really matter, rank 1 builds still had rare weapons in them just because they add a lot of heat or drained a lot of energy. Energy also didn’t really play a role in that era, physical was mostly people’s main mech and heat as a second mech.
Because heat and energy played less of a role the game was a lot about tactic before than it is now in my opinion. Most weapons had a limited number of uses, so you really needed to think what you were planning on doing before your turn even started so that your enemy wont be out of reach of your weapons that didn’t have any uses left. That aspect made me actually like the game the most, the actual thinking before your turn as planning ahead on how to survive.
Nowadays you see few to none people using a turn to walk or jump, this was always used in legacy, people moved and moved just to stay in your weapon’s range, while staying out of the enemy’s weapon range.
Also your torso would limit your weapons and modules, instead of a weight limit. Not even all legendary torsos could equip 4 side weapons and 2 top weapons!
But this was a little compensated by everyone having every possible special (drone, grapple, etc…)
I have never really played seriously with shields, i never liked them because they would suck up your heat or energy, which you didnt have a lot of in legacy. And without energy most specials couldn’t be used
One of the things im most sad about in Reloaded is the fact that they removed bullets and rockets. Those things could determine if you would win a match or not. Because in legacy you had a choice;
Either you have a lot of rockets and bullets so you could fire your weapons and drone that do high damage.
Or you would invest in heat/energy modules and resistance modules.
If you would like something specific to be explained further just let me know