That is not the correct fix for this bug. In the first instance the user simply installed the wrong package and although the message displayed in deluge-gtk should not have been an exception message there was no loss of functionality (as a thin client) and the proper dialog box to disable classic mode was displayed so this bug was never grave nor required any change to dependencies.
cgreco detailed that it was by design that libtorrent is not included in deluge-common and he referenced the bug report asking for the split packages to save installing libtorrent. I am quite surprised that this was completely ignored. I thought about disabling classic mode by default for deluge-gtk but this is not a good idea because displaying the initial yes/no dialog actually helps users who may have accidentally installed only deluge-gtk. So the solution is simply to present the user with a nicer message dialog which I have now committed to the Deluge repo and attached.
7ef7cc41b6f001220e83bcb34454e8804d2b1101.patch
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