Engineer is my absolute favorite class. Discovering this class really made GW2 10x better for me (still a good game though without Engi). I mostly play PvP and roam in WvW. Some thoughts on this balance patch:
Positive things first:
In general the changes in Tools traitline are really good. The condi cleanse makes it a viable option for some gadgeteer build and brings in some alternatives to elixirs and alchemy.
Shield changes are really good. The philosophy of removing cooldown reducing for weapon skills in traits is in my opinion the right direction.
Buffing Grenades is okay. This will bring also back some damage for F2P players on core engi (if that is even relevant).
Same with Enhanced Capacity Storage. Holo is currently still viable in PvP but this change will move it away from the edge of falling out of viability.
Buffing Coolant Blast and reworking Cauterize is good. This could be now a viable option instead of healing turret. Lets see how relevant the condi cleanse is, as Holo often lacks condi cleanse.
Buffing Photon Wall is good, it will be something for the S-D-build. Maybe bring in some additional Exceed skill? Bring back Hard Light Arena? Or Spectrum Shield?
Now some things which I think are good, but not good enough:
QUESTION: if lesser utility goggles trigger AFTER using a heal skill, are you ever able to use it for stunbreak? Isn't it weird to have a passive stunbreak on something you cannot use when stunned? Somehow useless then, or am I wrong here?
I still think elixirs outperform every gadget. Gadgeteer builds and Gadget skills will still be a niche thing, if you want to switch things up and are bored of elixirs. Gadgeteers will still be hard to play with less reward then every elixir build. I think it would be worth to look at some Gadgets again and buffing them (maybe an evade frame on rocket boots with higher cooldown?)
Kinetic Accelerators: I think it is good to remove the quickness regarding PvP as it destroys some pretty annoying meme builds, with which new players got farmed in lower PvP. It is always good to have an eye on that as we need new players in PvP. But where is the spot for Scrapper now in PvP? Some tanky do-nothing build? Some weird utility-teamfight build? I don't see any place for Scrapper in PvP now. Maybe the change is a good thing for WvW zerging, because it was to oppressive. Lets see how this turns out.
Please have a look at pistols in the future. They are pretty clunky to use. A rework could bring up some potential for a condi build besides Mechanist (maybe a Core build?)
And now the BIG bad thing:
The change to gyros totally destroys Scrapper for me. It kills nearly every uniqueness of that class. Gyros currently are perfect in usability, because it is possible to keep allies and enemies in the radius of their effects. It needs some skill to position yourself right but it is also not too hard to use Gyros effectively. With the change, they become completely nonsense. Gyros have a strong effect over time, but a weak for the moment. So every enemy or ally, who does not stand in the gyro field, is not really effected by any means. And enemies as well as allies never stand long in one field. As an ground targeted AOE, Gyros cannot compete with other AOEs from other classes. The whole selling point is their mobility. I understand Gyros have to be nerved in WvW, but why not just turning the numbers ridiculously low instead of destroying a whole mechanic?
