I don't think you really get how a modern day dictator operates....they don't need to apply those "mechanics of terror", is more about doing whatever you can to stay in power and ignore the will of the people if necessary, that includes but is not limited to:

1.-Fraudulent elections (which you can do)
2.-Sending the military to stop protestors (which you can do)
3.-Brainwash the mind of the people with propaganda by having total control of the communications (which you can do)
4.-Cherry picking dissidents and rivals and "make them disappear" via arrest or straight murder (which you can do)

so yeah...this game is pretty dictatorish...

Are you ok Sokar? :P

Joking aside, I think Tropico touches on many of those themes, but perhaps not as overtly as you’ve put it. You could always choose to execute a citizen in Tropicos 4 and 5; is that not the case here? (I don’t own the game yet). I don’t recall public executions, but then I haven’t played Tropico for a long time either. It looks like Secret Police were dropped after Tropico 4, so maybe they’re due for a comeback?

I think they want to avoid referencing fascism and some of the more extreme examples of population control you mentioned (broadcast executions: yikes!) in order to not drag the style and humour of the game down too much towards a bleak dystopia; or push the age-rating up. Fascist ideology is covered somewhat by the nationalist and militarist factions however.

I fully agree however that one of the basic premises of the game is that you should be able to play as a bad dictator; and they imply this themselves a lot. I believe some of those things you mentioned came in DLCs for Tropico 5, such as in Espionage; Inquisition (spies); and Generalissimo (commandos/paramilitary). Maybe they will again; but that leads me to my next point:

I always thought new versions of Tropico should come with all the previous building and occupation types (including DLCs) so the game can continuously grow in depth and complexity; but the developers obviously don’t see it that way. They probably want to sell something that feels a little incomplete in order to encourage future DLC purchases. I’ve gone on record (early on) to say the heists and world wonders are silly and they should’ve put those resources into including more of the buildings from the previous games (and DLCs) and/or more missions: T6 has 15, down from 20. World Wonders sounds like a classic executive decision to me: purely marketing driven! I have no problem with them scrapping Dynasties however, as they were almost equally annoying and useless.

Rebels were always a problem in T4, but I don’t recall that being the case in T5. This contributed to the suggestion that the game was being dumbed-down and pacified for a wider audience, and I certainly hope that hasn’t continued any further because it would ruin what makes Tropico great for me. I recall a very difficult achievement in T4 to do with terrorists blowing up your Mausoleum, so maybe we could see similar themes in a DLC.