Is decap guardian possible?
Possible? Maybe.
Worthwhile? Probably not.
I’ve build some builds with this strategy in mind when I just wanted the “Interrupt X players” daily achievement out of the way, but your knockdowns are either on a long cooldown, on weapons that aren’t worth taking for this strategy or on skills that aren’t awesome. On top of that, you have little in the way of actually keeping people of the point when you actually get them off.
If you do end up playing the build, you’re going to have to focus like crazy on positioning. Mistiming Sanctuary is going to mess you up.
In terms of weapons Hammer will be a must. It’s your most available knockdown skill with Banish and Ring of Warding and Zealot’s Embrace help you keep the enemy off-point. Apart from that the Hammer gives you a small amount of extra survivability with the protection boon but that’s not something you can rely on in PvP.
Your other weapon choice would probably be Scepter/Shield for the knockback on the Shield and the immobilize on the Scepter. It’s a shame the Staff doesn’t offer more control options, because Line of Warding would be useful.
With utilities you don’t have a lot of options. I’d say Sanctuary is a must-have skill. Other than that you probably want Bane Signet for the knockdown and Signet of Wrath for the immobilize. And since you already have two important signets, you might as well take Signet of Resolve as well.
Traits leaves you with little options. You need to lower your Signet cooldown, so Signet Mastery gets taken. Both Consecration traits are really, really useful to get the most out of Sanctuary and you want to hit that skill as often as possible so both Consecration Mastery and Consecrated Ground get taken. Might as well take another trait in Virtues to get Absolute Resolution since we’re at it. Inscribed Removal gives you another way to make the most out of your Signets. The extra traits are a bit more free, but I’d certainly pick up Binding Jeopardy since you’ve got every immobilize you can take. This gives you this build.
The other option, relying a little more on your weapons is this.
All-in-all you’re creating a pretty suboptimal hybrid build that does the same job of a Hambow warrior, only worse.
Guardian currently has very little CC capability. You’re better off going with a hammer on a warrior.
If you like guardian but don’t want to play bunker, try a meditation build. It’s offensively focused and much more fun than a bunker build IMO.
If the goal is to zoom to a point and 1v1 the person there thus decapping the point, you might think about spirit weapons. They are quite solid for duelling.
Anet lied (where’s the Manifesto now?)