In Dolphin you can embed an integrated terminal. Handy, I thought! But if you enable it, then every path change caused by navigating to directories in Dolphin, is stored in the history of the terminal (in other words, when using the "up" arrow to scroll to previous commands, it shows all these path changes).

That makes the history and up-arrow feature quite useless, the actual useful history is hidden behind many many unneeded path change commands.

So I can't actually use this feature.

Is there any way to let Dolphin not store path changes in the history of the terminal, or is there any hope that the KDE developers will do something about this?

It should obey whatever bash's (or the equivalent of other shells) HISTIGNORE variable says, so setting that variable in say .bashrc should solve your problem.

I.e.

export HISTIGNORE="&:ls:cd:[bf]g:exit"

Will that disable only history caused by Dolphin, or also if I manually type cd?

I'd still want manually typed cd paths to be in the history (example: I always use the history to go to a cd command that brings me to the folder of a certain game which I then start with wine).

In that case, forget what I said. It will be applied by manually typed commands as well.

You could alias "cd" to something such as "cdm" which may work around that restriction.