It's interesting to me that the opposition to "success with complication" is described as denying some inherent measure of player expectation --- "As defined by the rules, my dice roll plus modifiers was high enough to succeeded at my action declaration, and should therefore succeed."
For RPG play, the nature of success is ALWAYS constrained/framed by the fictional state in which the action is attempted. From where I sit, it seems a bit . . . odd, I guess, to complain about a rule system that specifically indicates that complications
will be introduced. A GM is given full ability to introduce complications
ad hoc, at any time . . . but having it hard-coded in the rules is somehow badwrong?
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For example, in some groups I've played with,
@hawkeyefan 's example of more guards stepping from the shadows with drawn swords would be decried as a "foul", because the GM should have allowed the players/PCs to make an attempt at
noticing those guards first. It's a specific type of group social contract, where the GM is only ever allowed to introduce risk in a fashion such that the players have some ability to mitigate it. If you're coming from that narrow view of play, I could see how introducing complications feels like a GM "cheat code", because old-school dungeon crawling is all about "smart" play allowing the player to eliminate risks.