Currently, I can add arrow with "Continue" action, or add forward/backword arrows that I either have to select marker, and enter the unique marker name, or select frame and indicate timeframe.
How about function that let's the software do the work. That is, select marker option and choose "Go to Next Marker in timeline"
"Go to Previous Marker in timeline"
At publish time, Camtasia with identify the correct locations for this hotspot arrow functionality (instead of requiring developers to explicitly state/select, which can be very time consuming).
Arrow next/previous functionality is very standard feature that most applications should have. You already build the TOC, so should be able to know what the next marker is and generate correct code.