I tend to go against related TU/bonuses, for the
following reasons ....
1) They're a matched set. If
the bonus stinks, you need to replace it. If you flub
the TU, you also eliminate the bonus. More work for
the TD.
2) Each TU becomes worth much more if
the TU and bonus are more than tangentially related.
Early negs are also more severely penalized. I'd guess
that this is less of a problem in HS because depth of
knowledge is more limited.
3) Breadth of Knowledge -
topics are cut in half. This can severely skew results
if one team has specific knowledge of four or five
questions. I also tend to like it when more subjects are
asked.
I'm not necessarily going against this format,
however - tournaments can and should try new formats - I
just think that there are some valid reasons not to
include them.