Games tend to come in two flavours – strategic and reactive. There’s a saying that says the best laid plans go to crud once the first shot is fired but there’s still always the need for a plan.
MMOs have a basic strategic element. You are given a finite toolset and resources to accomplish a task. You might not know what that task is exactly but you have an idea of what the enemy toolset is. The challenge in PvE combat is learning the pattern of that enemy toolset. Since the penalty for failure is time, there’s no real need to develop great reaction skills. PvP games however, the penalty for a loss is an equal loss of power/prestige, reaction skills are important. Think of the FPS games like Call of Duty. It’s next to impossible to properly guess what the enemy is going to use but a strong clan is going to wipe up nearly all competition.
XCOM follows the adage from above. You can plan as much as you want but if the enemy decides to through 3 mutons, 2 berserkers, a cyberdisk and 6 thin men at you, at once, your plans are out the window. The game is paused though, so you do have time to think of a strategy but your odds are drastically diminished.
When you are entering an unknown area you turtle – ie take the most defensive position possible to survive while analyzing the enemy’s attacks. Some games penalize this, some are neutral but a few actually reward the playstyle. XCOM’s Overwatch ability, where you sacrifice movement in order to take a reaction shot on any nearby enemy, allows you to play in a defensive mode while shooting. Other than grenade launching enemies, your best bet is usually to find cover, wait a turn, then use 1 guy to explore for enemies, find them, then bring them back to the trap. It’s Super Effective!
Then you get missions where you have to be offensive. The Terror missions task you to save civilians from enemies. You need to move through the map, find them, save them, and not die from the enemies trying to murder everyone. This is a challenge as most enemies take 2-3 shots to kill while your guys die in 1-2. The bomb diffusing mission is altogether different. You have X amount of turns to move across a map or the mission fails. You can gain more turns along the way by disabling power sources but again, you have to expose yourself to massive enemy numbers. My recent example had my 6 guys against 18 Thin Men. Who spit AE poison and when they die, release AE poison clouds – which you have to move through to get to the end of the map.
I find this a good mix though, as most missions are defensive and you get the odd offensive minded one thrown in to mix it up. Plus it’s always fun to mind crush someone from outside of grenade distance.