If he's relying on crits for dmg, then weakness affects the crit build too. The only way it wouldnt matter is if he was some kind of bunker build that combined crit might procs with altruistic healing or something along those lines.. but then dmg isnt the name of his game, the +boons for healing are.
I'm not sure quite what you mean...critical hits override the "Glancing" hits that Weakness causes you to land. If weakness normally would have halved your damage on an attack, but you crit on that attack instead, you do full crit damage. Builds with a higher crit rate, then, are less susceptible to the damage-reducing component of Weakness.
In regard to the OP, when you say your build isn't the issue, how much are you willing to change it? As it stands, Power is probably going to be the more efficient stat for you, because you're relying fairly heavily on the Minor Accuracy sigil to boost your crit, and you still top out at a percentage that isn't optimal for a crit build (also, just to let you know, the Superior Accuracy sigils you have listed in your Sword/Shield don't stack, so drop one for something else). More investment in the Radiance line could change this, but that could require some fairly dramatic changes to your build. Your other option would be to swap Amulets if you wanted to pursue a crit spec, but you'd end up being less tanky if you did so.
I'll make the comment that while good damage specs do need high power, I've found very few that truly excel without a high crit rate accompanying that power (45-50%, usually). I have a casual Engineer build that runs with 3404 power, but if I don't crit on my attacks, I'll still only hit heavy-armored characters for 500-700 damage per shot with my Rifle. On a crit, that damage rises to around 1500, a dramatic difference. Without crit, the best you can usually do is put some pressure on opponents while surviving long enough for help to arrive.
Final thought - if you want a durable Guardian build with high crit and power, I'd recommend switching the Hammer for a Scepter and your choice of offhand. The Soldier's Amulet and Right Hand Strength is the epitome of a tanky-DPS setup, and it sounds like it would appeal to you, based on how you've described your playstyle. The stats on a Soldier's RHS build will vary depending on your trait and gear preferences, but the version I run has 2945 base attack, 46% crit rate, 38% crit damage, 3k armor, and 17.5k health. It's very much a half-bunker, as you described your current build, but it can also put a lot
of pressure on opponents, and it will frequently score kills through a game while dying very infrequently.
Here's a link to the build, if you're interested. If you're not, then the changes I'd suggest really come down to how much you're willing to modify your current spec.http://gw2skills.net...ItwYgxBiNEvQmEA
Also, another (more traditional) version of the Soldier's RHS spec, from the Team PZ forums (I like mine better, but I'm biased):http://www.intothemi...6wk2l3IBl3IB6BC
Hope this helped!
Edited by Soryuju, 18 December 2012 - 11:42 PM.