See here and here for more of this.
Bosses.
We love 'em!
Right?
Sadly, 4E solos, in general, are pretty damn feeble.
The mechanics and powers of 4E mean that a solo is going to have the stuffing beat out of it, especially if the party has good control.
Status effects becomes incredibly powerful when they're affecting the whole encounter. (since a solo is worth a full encounter's worth of creatures)
Even simple stuff like Marks will have more impact than 'normal'.
So for a Solo encounter to be a memorable and cool experience (because where is the fun in having a dragon if the party kill it in two rounds without taking any damage), they need a reworking.
1: Independent Actions.
4E is not used to fighting single monsters. It is mean to have multiple ongoing threats. And a lot of excitement is lost when there's only one thing to care about. So Solos need something that's going on. Minions are a good one. A steady trickle of creatures coming on the board will both make the party cautious of being swarmed, give the AOE fellows something to do, and enable the encounter to threaten the squishies that are hiding in the back because the Solo can't get to them. Environmental effects that must be avoided or overcome are another good one. Whatever will ensure that everyone is in danger. It's too easy to end up in a deadlock between the solo and the frontliners with the ranged people just standing there. (some of the Catastrophic Dragons have some very cool fluid auras)
2: Multiple turns.
Some Solos and some Elites have this. (Yay, Tembo)
Solos should have it more often. When the monster only gets its series of actions after the whole party has gone, it becomes an exchange of blows with little for the players to react to. In a full encounter, there's a constant stream of changes to the battle, a Solo only affects the fight once a round. Change that. Giving multiple initiative counts is one way, or ensuring off-turn free actions also works.
3: Condition resistance.
Having a monster stunned/dazed/dominated or even a well-placed prone can disable them.
When a player can shut down a whole fight for a round, this ruins the drama and sense of threat.
When a player can put a Save Ends effect that shuts down the encounter until RNG says so, that's also bad. Multiple turns (2) can help with this, but I suggest making Stun and Dominate effects drop down to dazing, to prevent an encounter shutdown. Or Independent Actions (1) in the form of reinforcements or more dramatic field effects are also a good one.
4: States.
Not necessary, but the further you go into a game, the longer fights take. And whittling down a 400HP boss can end up repetitive. Having dramatic, combat-altering changes can bring new life into an encounter. Changing abilities, affecting the field, dramatic changes in tactics, they all help keep things fresh.
5: Damage awareness.
Make sure you do damage. You don't want an early boss to be shut down because the cleric gave everyone Resist All 5 and your solo deals DoTs. (I did that, it sucked) You don't want your boss to tear a party apart because it has three high attacks a turn and gets three turns a round. (Assuming you're not planning to kill PCs) A lot of Solos have the ability to make multiple attacks, but they often lack the damage potential to be a real threat. A level 7 solo that has 2 attacks for 1D8+6 is a complete waste of time. Even with 2 APs, you're not going to be a threat.
6: Don't be a one-trick pony.
Make sure your Solo doesn't rely on one mechanic too much. A solo that keeps blinding everyone discovers that it is just making the PC with the AoEs useful and making everyone else feel like a waste of space.
A creature that relies on DoTs can be shutdown with the right power.
Same for AoEs, Save End effects and other conditions.
Always have more methods of attack in store. Also, the more abilities the Solo has, the more dynamic the fight as you can change tactics.
I'm saying that you need all this. You can take any of the old boring Solos and mix in 1, 2, 3 or 4 to make it interesting. It's also more work the more elements you put in.
But a good Solo can give you great mileage.
Here's an early example I used that served me well.
The party ends up teleported into a large cave supported by four pillars. They are faced with a expanse of stone, and a giant flaming screaming skeleton atop a giant egg leaking lava.
As he tromps around screaming, he starts by making multiple Reach attacks and a minor action/reaction to push the melee fighters around, or sucking heat from in front of him to fire a super robot chest laser beam cannon attack. The giant egg starts spitting out globs of lava that form into minions that chase down the casters, and leave pools of damaging terrain where they die.
When he's brought to bloodied, he leaps onto the egg and cracks it, causing lava to spill out and start filling a large portion of the room. He then starts going around trying to knock the pillars down onto the PCs, potentially causing large damage, but also creating safe platforms for the players to not get seared. And the number of lava minions increases.
Throughout, there is an increasing damage aura around the Solo, and descriptions of the cave beginning to shake as the pillars are knocked away.
A damn sight more fun that Sir Keegan.
