You can already change the duration right in the sequence just by dragging either end of it. And there is already a Duration for the effect in the Effects Control Panel which you change by clicking on it.
Actually you adjust the transition in the Transition Window.. but the OP wants to change the Default Duration at some location other than the preferences.
I believe transitions are "crafted" and not just applied automatically. I dont see the need to do this any other way than what we have,
Too much dumbing down of the editing craft already IMHO
I feel as if my editing method is not fully understood. Jim Simon, If I am using 6 - 12 frame transitions and working from a certain zoom level, then using the mouse method is more difficult. Shooternz, I believe that because this would really be used by a fast editor using the shortcut keys ctrl-D and ctrl-shift-D it is definately not dumbing down the system. The current problem is that setting default transition duration is a bit clunky, and when it comes to editing speed the quick access to a default duration is important. A transitioning issue that could be better is not allowing a user to overwrite a transition with a new default duration transition by hitting ctrl-D. That mouse is useful, but very tedious for more than one reason.
Is the "Transistion Window" the same as the "Effect Controls" window, but when clicking on the transition? That is better for sure than timeline transistion edits.
The easiest workaround and solution in my case would be to add a spot in the keyboard customization prefs to bring up the preferences for default transition duration. Example: I hit ctrl-alt-d and up comes the general preferences with default duration. (Maybe you can do this already and I don't know about it?)
In any case both of you helped me to understand other editors workflows a bit more. Thanks for the replies.
FWIW (my edit workflow)
I have my default transition set at 30 frames. (This covers zoom levels usually)
I apply that using CTRL-D often knowing I will adjust it.
After previewing it I will simply drop into the transitions window to "craft" it by duration or position.
Some projects I will temporarily change the default. (Longer and shorter)
Tends to be rare in my kind of work that I would use much variation in transition lengths across a program. (TVCs) . They can alter the pace and rythm just as much as cut duration.