I apologize for the length of this, but I happen to be a wordy poster.
The tl;dr version: consider swapping traits to other tiers to account for their power instead of completely and quickly revamping them (i.e. kit refinement).
This has to do with the changes to kit refinement and why other avenues of balancing it do not appear to have been considered. Whether or not the nature of the changes are good or not is a discussion that is already being had all over the engineer forums and is not intended to come over here (although I can not be responsible for the comments of others).
The impression I have generally had is that the development team attempts to make incremental changes in order to not introduce changes that have drastic unintended consequences. Being a software developer myself, I know why this is a good methodology.
In regards to this, I felt the changes to kit refinement in the last update were a bit odd with regards to this development strategy. Every ability bears no semblance to what they used to be, and the global cooldown introduced in the last update was made twice as restrictive.
It strikes me as very unlikely that this could have been reasonably tested and given serious consideration in regards to balance. If it had been in the works for some time then perhaps my concerns are not valid, but I will assume that this is not the case since the global cooldown was originally applied in the previous update. In addition, there is clear evidence that the new kit refinement abilities are copy-paste rehashes of existing abilities, which means they could have been implemented much quicker (for instance, the character will sometimes shout “Slick Shoes!” when activating the glue on the elixir gun).
Regardless, I feel that the team is not utilizing an avenue of trait balancing that they have had available to them all along. Specifically, I am referring to trait tiers. I recall a statement made by a developer when this was introduced back in BWE2 whereby they described that the best builds were always 30 in one trait line and 10 in all the others. This allowed players to pick the best traits in each line and still specialize in whatever kind of trait line bonuses they wanted. As such, the traits that were “better” were moved up to the higher tiers, meaning players would have to invest more to get more.
In regard to kit refinement, this is an adept tier trait. By definition, it should be less valuable or useful than traits in the master or grandmaster tier, at least in a general, non-situational sense. However, I believe that most players and probably most of the development team regard it (or at least used to regard it) as one of the most powerful traits in the Tools trait line. In particular, it enabled the 100nades-style builds and doubled the healing power offered by the elixir gun.
As such, would it not have made more sense to adjust the tier that this trait resided in? Let us look at some of the higher tier traits that should, by definition, be generally more useful than kit refinement: