So long story short; i had a build up to a dark side force user that was engaged by my players. This was going to be a fight for their lives.

Then this sequence of events occured:

1) Player1 gets 3 advantage and causes BigBad to drop his lightsaber.

2) Player2 force pulls weapon away

3) Player3 fires light repeating blaster. Rolls awesome and with no weapon a reflect isnt possible.

4) Bigbad goes for an unleash strike. Ouch, but not that ouch.

5) Player1 stabs his face off. No parry.

This really made me see the advantage of disarm. I am not sure what the defence against it is.

Also unleash is underwhelming.

Did you pit a single nemesis against a party? He was asking for it.

Step 4 is where the Bad Guy went wrong. His next actions should have been Move The Hell Away, Move the Hell Away again, either under cover, out the door, or away from the people shooting at him.

Then for his action? Force Move some crap in the way, so he can escape, or flick the switch on a transparasteel barrier so he can taunt them from safety. Or push his "To me, My Minions!" button on his comlink. But just stand there and fight? That's a terrible idea!

He did have 2 decent minions actually. I simplified this to illustrate what happened.

You are 100% right. I needed to play him with a better self preservation instinct instead of acting like a video game character.

That said, I can see a very viable tactic being to disarm and then have the gunner gun.

Well, there is the Resist Disarm talent.

Few things more minions is always a good idea, especially if you happen to have the book that came from AOR GM kit for its squad rules or lacking that use the imperial valor talent (some NPCs have it but don't have my books on me at the moment to give exacts in which). Alternatively perhaps he could spend a manuever (and maybe flip a DSP) to have a bulkhead slam down seperatinf the party while minions engaged those cut off from behind, etc. Sometimes though the party's just going to roll well and that's ok, just take steps to give your opponent plan b, c, and d if they're supposed to be a "big deal" at the end and never leave an early opening for focus fire form a full party as very few enemies can stand that since players are clever and will more often than not punish you for it.

You could also add some dilemmas to the final encounter if you still want to use only one 'boss' character. This would play to other character strengths other than just combat. Maybe they need to stop a self destruct sequence, sabotage some crucial ship/computer etc...anything that will take place concurrently with the 'final confrontation' so not all characters are available to gang up on the boss. And sometimes players can still surprise you and that's fine. I had set up an encounter once with an inquisitor vs a force character, splitting the party to complete other objectives so it would be a 1 on 1 fight. The party managed to come up with a plan to eliminate the inquisitor during the fight by using the environment....sure it was a catastrophic decompression into space, but still it was creative.

I generally give Nemesis level Sith/Evil Force Users Resist Disarm. But the other tool in your chest are Destiny Points, you can as a GM always flip a DSDP to change something within the scene and have your BBG grab his sabre/weapon before it gets away from them. The good thing about this is that you can't keep doing unless you have DSDP to spend and it give the Player's a LSDP to use later.

The point is to keep the tension high for as long as you can without nerfing the Player's actions or acting unfairly. Using DSDPs allows you a freebie or two to keep your BBG dangerous. As long as you don't over use it the exchange should be okay at your table.

Some ideas:

Still require an opposed Discipline/Force Power Check on the Move to pull his weapon away from his immediate personal space (even if he's no longer holding it). This might be a nice middle ground between just saying no to the BigBad being disarmed and making them just as easy to "cripple" as any other NPC.

Use Protect as an Out-of-Turn Incidental against non-reflectable/non-parryable attacks.

Use Move to disarm/grab the lightsaber back (and if the Nemesis has the Force Is My Ally talent do it as a Maneuver).

Squad rules from the AoR GM kit - I'm a little rusty on those rules and I'm away from the booklet but I do recall it lets minions take hits instead of the "squad leader".

You could also add some dilemmas to the final encounter if you still want to use only one 'boss' character. This would play to other character strengths other than just combat. Maybe they need to stop a self destruct sequence, sabotage some crucial ship/computer etc...anything that will take place concurrently with the 'final confrontation' so not all characters are available to gang up on the boss. And sometimes players can still surprise you and that's fine. I had set up an encounter once with an inquisitor vs a force character, splitting the party to complete other objectives so it would be a 1 on 1 fight. The party managed to come up with a plan to eliminate the inquisitor during the fight by using the environment....sure it was a catastrophic decompression into space, but still it was creative.

All of this in one big boss battle gauntlet for the fighter to keep it difficult for them all.