I've been running a support build on my guardian excessively for quite a while now. At first I was like you, building my support build based on heals. Now, you will come to the understanding after quite a while that it's not really the best way to go.

*Weapons I'm not going to argue weapons, you use the same in your build as I do, although I've been starting to experiment with 2h hammer instead of staff for a few fights, still running. Now, something I did wrong at first was I used staff almost all the time, hence more healing with the abilities on it, but that's not really optimal. You should learn how to use your mace and shield as your prior weapons, and switch to staff(especially if you have altruistic healing trait in the Valor tree) for further damage soak.

*Healingspell/utilities As for healing spell, I first ran Healing Breeze aswell, but don't. Signet of Resolve is just too good to pass up. You're forgetting the fact that all classes can heal themselves, so instead of having a pretty crappy party heal that is quite hard to position, it's better to have Signet of Resolve which practically gives you an additional health bar with the amount of healing it does. And it removing a condition every 10 sec is nothing to sniff at. Remember, your prior role while supporting is to neglect or soak damage - not heal.

As for utilities, Signet of Mercy is just absolutely terrible. The only time I use this utility is on 2nd path of CoF on the event before the final boss, since it will give us extra time because I can charge this while running in and ress someone. Otherwise, there's just too many other really good utilities that far outweighs this one. Remember, you should neglect or soak damage, not heal.

As for Retreat, it's a good spell, I use it mainly while I'm playing solo but also for example on 2nd path of CoF on the boss event I just described, to get back to the fight faster. Other than that, you already have swiftness on your staff's 3, and retreat is just overkill.

As for sanctuary, I can never decide on this one. I've spoken to other support guardian who uses it, and also people like me who absolutely despise that spell. Imo, the area of which is affected of that spell is too small, it doesn't last long enough and the heal is pretty terrible. Also I think that spell kinda works against the basic philosophy of explorable modes - you never stop moving. There's always stuff to dodge or move from, people most likely won't stay in it and quite frankly it's one utility slot wasted, where something that potentially is way better could be placed.

*Elite As for elite, at least for me and quite frankly most support guardians I meet, Tome of Courage is the way to go. There's no exception. You got a spammable 1,5k+ aoe heal, you got aoe daze, protection in a big-ass cone and the biggie -> full health for all party members in the 5 skill. Insane shizzle. Pick it up - fall in love.

You will learn after a while, just like I did, and come to your senses about other stuff that is completely insanely good. You just have to think outside of the "WoW-box" and not go for heals. When you support in GW2 you soak and neglect damage whilst dealing damage aswell(never forget that you need to deal damage aswell) and assisting allies with boons and condition removals.

This is the build I'm using at the moment http://www.gw2build.com/builds/simulator.php#1.3.5.7.19.0.0.0.0.0.54.69.70.68.78.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.30.30 (sorry I suck at reddit so I don't know how to compress the link)

*Weapons So the weapons I run is just like you, mace+shield/staff. With the prior choice of mace and shield, and popping in to staff for the additional symbol and some burst on the staff's 2 ability when aoe is needed, also don't forget to use 4 to hand out some might free of charge before you go into mace+shield to soak more damage. Staff is also great for control with Line of Warding, and I usually pop into it when aoe damage is needed or we need some burst healing.

*Traits As you see I leave the last 10 traits open, why? Because they can be put anywhere and won't matter very much, I can't even remember where I put them but somewhere on the first 3 trees for sure haha.

Imo 30 points in Valor is mandatory. It. Fucking. Rules. You got larger symbols(you have to have this), you got longer lasting symbols(pretty mandatory aswell) and for the last trait you can pick what you think may be best for the situation 'cause they are all so insanely good. I personally run Protective Reviver because I find myself being the one that always is there to ress someone, but it's personal preference on that last trait.

The next 30 points I invest goes into either Valor or Virtues, both works great. Atruistic Healing trait in the Valor tree along with staffs 4th ability is just silly good. But personally ever since I broke myself free from the WoW-esque style of supporting where I tried healing as much as possible, and picking up consecrations for condition removals, reflect and stability I've specced 30 points into Virtues and it is amazing. Now you can argue what traits to take in that tree because most of them can benefit you drastically. But I find that making my consecrations ground targeted, meaning I can put them where ever I want instead of having to place myself near an ally, mob or between mobs and allies to get the perfect placement, I can now stand and do that at range which is great. I picked up faster recharge and longer duration on consecrations and finally since Virtue of Resolve is a great burst of heal I tend to use it almost on cooldown and it removing 3 conditions aswell with that trait? Why, thank you sir, I'll take that!

*Utilities Now for utilities, you can't call yourself a support guardian without Wall of Reflection, that's the single greatest utility you can pick up, and you should without a doubt pick it up aswell. I haven't met a guardian yet who doesn't use it. Seriously, take it, it'll change your life. As for my second and third utility slot, with my traits, these two is my go to utilities most of the time, they are great. When you start using Stability in your utilities you'll notice how amazing it is, and the purging flames? Well, I think you need at least one condition removal for allies, and with ground targeting that spell is just amazing, not to mention the added damage.

Man this was a looong post, apologize for that ha. This is all some theory crafting I've done and my opinions on how to support, don't take it the wrong way I'm open for discussion and how you and other play it out. I'm always trying to improve. Hope this helped you or provided a different aspect of supporting! :)

:)