With the development of the Barbarossa and the No Step Back updates, Hearts of Iron 4 bring a more streamlined commanding structure, accompanying buffs, and experience changes.
The first changes a player may notice are the ones pertaining to the user interface. Military advisors are moved from the political sub-window and can be found below the High Command and Military Theorist portraits, which are now placed at the top of the UI.
Previously, only the Theorists gave daily experience bonuses, but with this update, new changes are in effect. All high command and branch chief will now generate experience appropriate to the branch they represent.
With the change of no longer being able to create a national spirit alongside an advisor with the same name, for example, effectively masquerading as the same person, the Advisor Promotion mechanic can be implemented.
"The introduction of a more connected Officer Corps", point out the devs, "felt like the perfect time to bring more of a connection to the Generals and Field Marshals that oversee your active forces, and the various military offices that advise your government." In No Step Back, Generals, Admirals, or Field Marshals can be assigned an advisory desk duty in addition to their status as field commanders. What this means is that the player will gain an additional character as a new advisor in their roster.
Paradox Interactive
As for the experience changes, the developers are ramping up the tempo, whilst having balance in mind. It would appear that the peacetime experience generation has received a buff, compared to that of wartime. A gradual change is what the developers are going for, with capping the combat experience, separately from other sources of wartime experience.
Due to the fact that we can expect more experience generation, the tank designer doesn't seem to be the only new way of spending it, and devs are hinting at other changes that will give players more options in spending their experience.
