Rather than come up with specific ideas for the new tactical items and set bonuses, I had some ideas about what abilities have the most potential.
1. Stim Boost - This ability, with the Revitalizers utility, makes the next Kolto Injection instant AND grants 10%, AND grants 20% less damage taken AND 5% restores health every 3 seconds. Will all those different aspects, it is very unclear what this ability is really meant to be.
I would like to see this be a prime candidate for a tactical item. It could grant two auto crit Kolto Infusions, like a Sniper's Laze Target. Or it could make Kolto Waves channel 50% faster. Or it could grant reduced Force/Tech damage received. Tactical Items would make it possible to turn Stim Boost into distinctly different abilities depending on play style.
2. Countermeasures - I would like to see a tactical item for this ability because currently it is only made useful by a utility. The ability to place two Kolto Probes with one GCD is great, and it being placed on an ability off the GCD, and with little base value works very well. I would like to see other options to augment this ability with. Maybe reset the CD of Recuperative Nanotech, or something more defense oriented.
The remaining abilities have less potential than the first two, but are still worth noting.
3. Shield Probe - This is a boring ability, but has room to add some interesting mechanics. Possibly increased shield amount, health on collapse, DR on collapse, ect.
4. Adrenaline Probe - A tactical item could change how this ability restores energy. It could reduces the CD and energy granted in half, witch would benefit a more single target burst oriented style. It could restore more energy over a longer period of time, and there are many other possibilities.
This last one belongs on the Wall of Crazy, but could be very interesting.
5. Infiltrate - A seldom used ability, with a very small opportunity to even be considered. A tactical item could completely change this ability, and give extremely different results based on the item chosen.
When it comes to Set Bonuses, my main thoughts are simply that the auto crit Kolto Injection is very important to the spec. It is so important that I would argue that it should be worked into the spec itself. Other than that, there are so many possibilities that it is hard to settle on a few ideas without knowing more about the upcoming changes.