[i know its a bit late, but we don't have any idea about future PT changes in 6.0 atm.]
You may know that PT is pretty weak with its DCDS, at least in PvP. I'll be talking about my ideas of new spells and abilities that would be nice for PT. Disclaimers : I do not do PVE, my ideas are mostly focused on my PVPer experience as powertech.
The powertech is the only class in the game that does not have a defensive CD to block damage. A new defensive spell is needed without being too strong.
My proposal: Like Hammond on Overwatch that activates an ability to offer extra life shields based on the number of enemies around him. The powertech activates this spell (Adaptive Shield) which would create shields depending on the number of enemies around him within a radius of 30 meters (4 enemies maximum and 15-20k HP per enemy). This is not extra life like Juggernaut, but "another life bar". That would last 20 seconds before life begins to decrease over time, and during those 20 seconds, he would benefit from a Buff that would reduce by 10% the damage received (which would make 16% for the Prototype Advanced (passive "prototype armor", level 28), and add another 5% to the pyrotechnics talent tree to balance between the two specializations. As for the Tank, an AOE would be created around it within a radius of 30 meters , reducing by 10% damage to allies who are in the area of effect). Such skill will require a fairly large CD (3 min?). If the "shield bar" is destroyed before the 20 seconds buff ends, the buff (and only buff with 10% DR for 20s) restart.
Why ? : As said before the powertech can not block the damage directly (no reflection, no Godmod, no vanish ...) It is a class that Facetank far more than the others and who suffers (hence the very small number of Dps powertechs in solo ranked). The powertech must juggle between 3 defensive CD's (Shield, Kolto and Hydraulic Manip [i exclude the Advanced Prototype mass taunt and the breaker]). A spell that "increases the player's maximum HP" would be less frustrating for opponents than having to play against a class that can return the damage or absorb it 100%, without exploding it in less than a minute. Since it isn't extra life, the WZ medpac won't be broken while used on it. Medpac would only heal up your "real life" and not the shield health bar.
Other 'new' spell: Chaff flare, distinct from the sonic missile. The chaff flire will increase by 30% the chances of defense for the advanced prototype powertech and pyrotech. The tank will benefit, like the Mercenary Arsenal, of two charges absorbing the direct Force and Techno damage. This would allow a new defensive CD for the Tank and Pyrotech, and to distinguish between a Multi taunt and a defensive CD for the advanced prototype.
As regards the abilities.
Some of the skills of the powertech are useless, leaving little choice in the talent tree. Here is a proposal for rework.
What makes the powertech original is that it is a mid-distant dps. However, this status has been nerfed with previous updates. Skills exist to deal with this problem but they are useless. Thus, the "Bracer Propellant" (Skillful tier) should increase the range of Rail shot for 10m and Magnetic blast, Energy burst and shatter slug by 5 meters in addition to being added to the "Pressure Overrides" (legendary tier). In order to replace a missing abilitie in the first Tier, we could have a passive that heals the allies within a range of 30 meters once Adaptive Shield is activated, up to 2-5% (like the passive "Assassin's Shelter" of the Sith assassin in Masterful tier).
Another useless skill is "pneumatic boots" (masterful tier). Why not add it with the last tier ability "Battering Ram" and add an effect on this ability: after making the first express charge, the Powertech is immune to pulls and knockdowns for 2 seconds (and not 4 since PT already benefits from hydraulic overrides).
One could add an ability to fill the missing ability, slowing the speed of movement of the targets affected by Deadly onslaught of 20% for example.
Finally, why not combine the abilities "Torque boosters" (+ 4s on hydraulic overrides) and "Overdrive" (+ 45% speed); since both of these are almost indispensable in all PVP situations (idk about PVE). There would be place for a new passive, which could add an effect on the Kolto Overload: Increases the damage done by 10% while the Kolto Overload is active.
We would have such a distribution : https://imgur.com/a/GLYNuFJ
Feel free to expose your ideas