Objectives have a critical importance of player guidance through the level. They can be direct (capture point) or indirect (take power-up). As i'm now developing maps for AW, all the power of objectives and their critical importance present to me. If tank games are common to you, you may know, that best strategy to win a match is to stick together. Those, who can gather up, win. But, with current matchmaking systems, where teams all the time is random, you can not hope that players will act as a team. So, how do you approach this problem, as a level designer?
Let's locate the problem. You need to guide people to the place where you want them to fight, right? What do you do? You build a corridor, so players can only move in two directions: to the fight, and from the fight. But that is not design, that's a cage. Of course, some games are designed to be a fight in a cage (fighting games), but i don't think we can talk about any meaningful level design there (or, we can, but it will be very special talk).
Of course, you can totally deny the existence of that problem and just leave players to themselves, giving them no meaningful explanation of your level topology in terms of using it as a tool for achieving victory. Just fight, i don't care, where on my level you will kill each other, that sort of behavior. But that's just rude, we don't want to be rude, are we?
Ok then, let us move on. Next solution, is to invent some sort of "sport" rules, like "capture the flag". This is not a bad solution, but it only good for certain games, if you want to achieve a feeling of serious war act, you have to step away from any kind of "sport rules".
Designating points on the map, as important for victory (domination) is good too, and it often can have good lore explanation, but this solution is quite far from being fresh. It is easier to name a game which is not using it, then count all the games that do. Although, this solution is still very good.
What else can we do? Well, i think it is time for us to get back to the roots, and recall the glorious PvP game of the past. For instance, Doom and Quake. Power-ups! Only now i start to understand all the glory of the design of pickable weapons and different bonuses, as a tool for navigating player through the level and into the fray. What do you need to do to win? Kill the opposing player. You can do that with weak starting weapon, or pick up that rocket launcher located over there, but your opponent also can pick it up. Brilliant, brilliant solution, a player knows, that other player knows, that player knows about a location of bonuses on the level, and that makes a whole new level of psychological tricks and traps for players.
So, why we don't do that in tank games? Well, actually we do, but first, let me explain why we don't. Let's face it: you can not make a tank to pick up a weapon that it does not have. This is far from being realistic, unless you are making a game about not realistic tanks, which, i hope, you don't, because such games - sucks (no offence here, just observation). And you can not make "realistic bonuses" that somehow make a tank stronger that it already is, for the same reason.
Ok then, what can be realistic indirect objective, which gives a player such power, that can lead to victory? My colleagues from Obsidian Entertainment made a great decision while designing GLOPS mode for AW. In this mode, player can "capture" a point, and that gives him opportunity to use one of the strategic abilities on the map, like: call an recon drone, that will scout part of the map for enemy vehicles, or call an airstrike at the small area. Such objectives, despite not giving a player victory itself, can lead to it, if used wisely.
Now, as a map designer i have one more tool to guide player movement through the map. Of cource, i still have other tools: clever use of map topology, that will give advantage to player holding this position, but those sometimes are too indirect and not very friendly to new players. Also. "advantage points" tend to work too well: once player hold is, he don't want to leave it.