Brood War Tanks could only be considered “better” than LOTV Tanks based their size (half the radius) and some limitations of the game engine (range was longer on the diagonal because range calculations were based on the x/y axes).
Otherwise it is a wash:
- The damage of both Tanks is roughly the same.
- The difference in attack speed makes up for the supply difference.
- The differences in buildup cost and support units arguably makes up for the difference in durability between equal supplies of Siege Tanks.
-The pathing changes work both for and against siege tanks. SC2 pathing clumps units up a bit more for splash, but the same quirks that prevent Brood War units from clumping as much also slow units down when there is terrain or another unit in their path.
WOL Siege Tanks were worse than both the Brood War and current LOTV version.
Both the early WOL alpha Tank at 60 flat damage and the later 50 flat damage variation (nerfed for light units) post-release lacked killing power against armored targets; and mech had no way to make up for that deficiency. The flat damage was also far too much for most light units, so its change back to an anti-armor focus like it’s Brood War predecessor was inevitable. The attempts to balance the StarCraft II Siege Tank with flat damage back in WOL arguably gimped it, costing the Tank a full 20 damage against armored units until it was finally rebuffed in LOTV.
From a design standpoint it is also a bad idea for Siege Tanks to have so much base damage. Tanks commonly rely on Hellions, Hellbats, or Widow Mines for support, or Marines in cases where Marine-Tank is viable: All of those units have an anti-light tendency that makes high base damage redundant, and they cannot endure friendly-fire from Tanks with such high base damage either.
Mech can use Tanks in TvP easily:
- Mech doesn’t have to waste extra resources on Medivacs, so the effective army is larger.
- It can rely on Hellbats or Widow Mines to keep the enemy off the Tanks. Those units can survive a decent amount of friendly-fire, and they don’t need to kite the enemy (thereby abandoning the Tanks) to be effective in combat.