You can install OpenOffice if you don't like LibreOffice, not that there is
much difference. The problem with the Software Centre is that it does not
show dependencies and gives little feedback, which is why I use Synaptic
instead. If you are using Unity then it runs GTK apps, but not QT which is
part of KDE. When you install KOffice in Synaptic it advises you that it
needs to install the KDE dependencies. I am not sure how well this works in
Software Centre. On my system (Kubuntu with Unity also installed) when I
switch to Unity KOffice is available. I am not sure about GNOME Office
because I have never used it.

I am not a fan of either the Software Centre or Unity (or GNOME 3). It is
dumbing things down to an extreme point IMO. Unity is fine for my netbook,
but on my desktop computer with a large monitor it is too much work and not
a fun experience. The Software Centre has some merits, but it is not
informative enough for me.

The lack of a menu in Unity makes it hard to fix your problem. I don't know
that the entries in the Launcher or Dash are editable at this point. I would
load Synaptic and try to Re-install each, if i had this problem.