We're talking about all races, not just Orcs. And in general, cold is definitely not worse, because against Necropolises or Dwarves, tactics aren't critical, and Elves and Demons will reach their destination even without tactics.
As for Orcs, who can reach the enemy in one turn? Executioners and Wyverns, but Ogres are usually not taken. For the rest to reach, besides tactics, you need to take the Aura of Speed, put on boots, and pray for smooth terrain. However, if you're waiting for exactly that kind of Orc, then tactics are indeed needed.

There's also a battle cry on the Offensive Unit skill. With a base speed of 5, you can add another 4 (tactics, Aura of Speed, blue boots, battle cry on the Offensive Unit skill), which effectively gives you 9 on the first turn, so if there aren't too many obstacles, everyone will reach the last row.

In the late game, are Orcs' stacks more dangerous than Cyclops'? No, I haven't heard that.

You really need a lot of Cyclops, for example, from the Dragon set; otherwise, some Kents and Goblins with claws can deal much more damage. At the same time, you have to keep the free Cyclops away from your army, and if the enemy attacks other stacks, it's scary to approach and defend them with Cyclops, because they can easily be lured into a counterattack on themselves. So, if it's not a tactic based on Cyclops with a bunch of stacks of leaders on speed boosts, then there's no need to focus on them.