Let's talk about placing markers during fights.

[linay]

However, with the new presets system....Why not allow it so that marks cannot be MANUALLY placed mid-fight, but still allow it so that Presets can change the placements of markers mid-fight, so when you go from phase 1 to phase 2 in a fight, and you need new markers, you simply click on the 2nd preset and it swaps it over. Something like that would be good.

Likely because they then have to make sure there is no flaw in the coding that would allow third party tool to piggyback on that preset exceptions and move the markers that way. So they just block it entirely. Or they just don't want too much automation during combat, including from in-game tool.