Just noticed this tonight, but now that my Saturday group is rotating between 13th Age one week and D&D 5th edition the next, we're experiencing a bit of system bounce again. What is system bounce, you ask? Well, it's that funny thing that happens when you try to move back and forth between two game systems that are very, very similar....so similar that most of the core mechanics and fundamentals have some analog between both systems....enough so that remembering which game does what actually trips everyone up at the table.
"How does coup-de-gras work here? Which system handles Sleep spells in what way? Wait is this the edition where I pop free or get an opportunity attack for passing through?" Etc. etc.
This happened a bit tonight with 13th Age. It also was tough going an entire evening without granting advantage or disadvantage to someone. The elegance of that mechanic feels like it should naturally trascend D&D 5E....it belongs in all D&D-likes now. The mechanic is so simple yet effective that the idea of moving back to something which doesn't do it....including 13th Age which has lots of innovative concepts....seems backwards and silly. So yeah, I may have to houserule it in for the future, if I feel like tinkering with the implications of the mechanic in 13th Age.
This happened some years ago when we rotated with Pathfinder and 4E, but the comparison was worse, for some reason, probably due to the laboriously rules-intensive natures of both systems. Thankfully it feels less onerous in the 13A vs. 5E comparison due to the much lighter rules mechanics.