Speed increase in TB is just AP increase, so there is no added chaos. BG was closer to TB in this regard than PoE with it's immutable fixed 6 second rounds. PoE utilizes the RT element better by allowing you to modify action speed..
You can modify your action speed in the IE games (both attack, full action and cast speed) and the WC3 engine as well (just attack speed).
I have no idea how you have become married to the idea that percentile modifiers to the speed of both attacks and spell actons is somehow 'utilizing RT element better' than another manner of handling unit actions in a real-time (or rtwp game). I am definitely of the mind that a stepped / less granular approach is easier to read/process. Copper Dreams 'ticks' approach is one example, where every speed increment to anything is always handled the same. That's how I would do it, rather than how Pillars does it with 10% here, 20% here -50% here and modifier multiplication rules. Addition is easier for people to understand when reading rules or trying to determine the benefit or malus of something in real effect, and the effects in actual play are easier to notice on screen.
An RPG is always based on another type of game whether it be FPS, Third person shooter, real-time strategy, turn-based strategy etc etc. PoE1 combat is still definitely under the RTS style combat umbrella, and PoE2 is no different, so I think it's perfectly reasonable to compare the two, just because you may happen to play the others against people, that doesn't mean that you can disqualify such a comparison.