Healing Engineer revisited

https://www.reddit.com/r/GuildWars2Builds/comments/abytrh/theorycrafting_wvw_healing_engi_revisited/ - same post on /r/GuildWars2Builds

So recently I decided to take a break from roaming on Holo and try out this Healing Scrapper I hear about so often. After a couple of hours in zerg fights and a few guild runs I came to a conclusion, that Scrapper brings very little to the while healing thing. Sure there's Rapid Regeneration and Defense Field, but after recent nerf to Superspeed share on Scrapper the traitline's usefulness skyrocketed downwards.

I decided to do a small brainstorm on what are the alternatives to Scrapper? What those alternatives bring and what do we lose?

This is a template of what I consider a base-line healing engineer.

As I'm dropping Scrapper, I lose Hammer, so an AoE stun, a bit clunky but generally good mobility skill, a block and a reflect. We also lose Defense Field (Bulwark Gyro toolbelt skill - AoE stability and projectile hate) and Rapid Regeneration (~158 hp/s, ~79 hp/s AoE heal).

The baseline I'm proposing is equipped with shield that provides AoE Protection (we'r not running Anticorrosion Plating so not that big deal), reflect (not as big as hammer2) and a defensive-offensive stun skill aka shield5.

Now we'r left with 2 possible trait lines and 2 empty utility slots, which gives us quite a few alternatives:

Tools

First of all it lets us spam Toolbelt skills more often. So the spike heal from Medkit goes every 14.75s. Also opens up a lot of alternatives:

• the adept traits we can pick are either Reactive Lenses to save us from CC, or Power Wrench, to get more block and an amazing Pull skill on shortened recharge.
• master trait is obvious - Streamlined Kits - so immobilize (very powerful) line with Elixir Gun and Magnetic Aura with Medkit (and Superspeed if we picked Toolkit).
• grandmaster traits give us a few choices - Kinetic Battery is good because Quickness goes well with Med Blaster. Adrenal Implant gives the least synergy but who says no to more invuln frames. Gadgeteer opens a nice variant - Slick Shoes can become extremaly powerful CC skill to catch people in Spellbreaker bubble.

Holosmith

• I'll start from the back and talk about grandmaster, which is an obvious choice for me - Enchanced Capacity Storage Unit. Goes well with utility skills from Holosmith.
• master traits are either CC: Zephyr or CC: Eclipse with the accent on the 1st one. Zephyr gives us the shared, spammable Superspeed everyone wanted and love. Eclipse gives a bit of personal stability.
• from adept traits, Light Density Amplifier gives us a bit more tankiness and Prismatic Converter a way to deal with condies.
• utility skills on Holo are generally a decent pick - Hard Light Arena as a boon spam field and a great CC from toolbelt skill, Spectrum Shield as a stunbreak to get out of hot situations, Photon Wall to get blocks and possibly reflections.

Other ideas

• we can also run Experimental Turrets from Inventions to get some projectile hate - for that we'd need some turrets in available utility slots, the problem here is turrets are squishy and one hit from Meteor Shower or Coalesence of Ruin means they are gone.
• Rune of Altruism + Mortar Kit spam to deal with conditions.

Problems

• lack of personal stability. Core engineer has a terrible problem with that - you either need to go with Elixirs or you are cooked. This build would gain A LOT if one Gadget could eventually become a Stability source.
• if Heat Therapy would trigger Medical Dispersion Field, the Holosmith version would probably end up as even better healer than Scrapper is now.

I invite everybody to join the discussion and point out any errors/variations I missed/possible solutions to the problems I pointed out.

Shouldn't the heal for rapid regen be higher? 5 targets and with traits/food MDF does something like 80%...

I wonder if comeback cure with anticorrosion plating and hard light arena would increase the regeneration output enough to make up for mdf.... In some cases with the heal-scrapper I get more outgoing heal from regeneration than from MDF in a fight, but usually MDF is ~30% stronger. It would offer stronger condition removal and has more direct boons... And the stability is not an issue witha decent guard in your group.It would allow us to use a sword, though, which is a much better option than the pistol.

Quickness on tools sounds great at first, but which toolbelt are you using to trigger it? F1 and EG-F should be saved. Most skills you mentioned have long cooldowns on their toolbelt skill or it has a very useful effect. To trigger the quickness at the right moment, when you need the heal, will be extremely difficult. This trait only really works in SD-builds from my experience.So, I highly doubt that the heal will be as good...I also don't see much benefit from traiting slick shoes to do cripple (one hit per enemy after its nerf), since you already do immobilize with elixirgun...Which would leave the enhanced endurance.