Algalon is not a fight you bang against until he dies. That fight is fought… on combat logs, and in discussion threads on guild forums.
I haven’t fought Algalon yet, but after thinking about this, I realised that there are two kinds of fights, execution-based fights and planning-based ones. To explain the difference, I’ll compare a few encounters.
An example of an execution-based fight is Heigan, in Naxx. It’s execution-based because the mechanics of the fight basically force a certain strategy. When there’s bad stuff coming out of 3/4 the floor and a spellcasting debuff around the boss, it’s pretty obvious that you’re going to stack your ranged away from the boss and stand on the safe part of the floor. So the fight comes down to your raid being able to stay alive during the dance and cleanse some stuff. That’s the entire fight.
Aside from bugs that allowed you to hide in one corner of the room and avoid the bad green stuff completely, Heigan doesn’t really require any kind of planning as long as the raid is aware of the mechanics. A lot of Naxx is like this, perhaps to its detriment. Look at fights like Patchwerk, Grobbulus, Gluth, Thaddius, etc. Every Naxx pug I’ve done has used the same strategies for all of these encounters, which I’m taking to mean that there isn’t a large element of planning to them.
Tristan used the example of Algalon, but since I haven’t been there yet I’m going to use Anub’arak. The execution element of Anub’arak is fairly simple (execution here meaning avoiding getting hit by spikes, using permafrost to the advantage of the raid and killing the adds in a timely manner). During an attempt on this boss last night, we were executing everything well. Unfortunately, the boss enraged before we could get into the Locust Swarm phase. What this meant was that our strategy was flawed.
Since we didn’t always tank the adds close to the boss, we lost a lot of damage on the boss and the adds from cleave damage, both from ranged and melee. So the fix is to change our strategy to maximize damage on the boss while also getting the adds down quickly. So the planning element of a fight comes, in this case, when the execution aspect of a fight is not so rigid as to predetermine strategy.
Another example of a planning fight is Vezax. The execution aspect of this fight includes avoiding Shadow Crash, interrupting Searing Flame and properly using Saronite Vapors to regenerate mana (on normal mode, anyways). But unlike Heigan, you can’t just explain to your raid “avoid crashes, DPS the boss and interrupt” in order to succeed. You have to create a strategy to maximize the uptime of Shadow Crash DPS time and get the best placement on the Crashes. I doubt that every Ulduar pug uses the same Vezax strategy, unlike Naxx.
If you compare the encounters in Naxx to ones in Ulduar, you may notice that Ulduar bosses, especially the later ones, are more planning-based than execution-based. Even relatively straightforward fights like Kologarn have some leeway in strategy. You can choose to only DPS the Right Arm when it grips someone in order to minimize Rubble, or you can kill the Right Arm and Left Arm whenever they are up. While not all Ulduar fights are planning-based (Razorscale is pretty clearly execution-based) on the whole they are more malleable when it comes to strategy.
Sometimes the optional choices in fights, such as kill orders, are linked to achievements, as with the Assembly of Iron. Other times they are simply decisions that need to be made, such as with Freya’s summoned elementals. Before going into the fight, you need to decide which elemental to DPS first and what % to stop at, when to switch, etc.
Encounters in the Trial of the Crusader are something of a mixed bag. Faction Champions is a strange combination of execution and planning because the “execution” aspect changes based on what your strategy is. Jaraxxus, on the other hand, is more execution-based. With Ulduar it seemed Blizzard was placing more weight on the planning side, but now I’m not so sure.