But, for most information, what kind of 'slowdown' are you talking about ? 1 second? or more? heh, hope it's not more It'll be quite normal to see some lag when the combat arrive because of the mass of code that the Combat engine must run But it's not suppose to spend more than a second.
Yes, one or two seconds sounds about right. It felt quite normal though, not like a bug or anything. Perhaps you could add a messagebox saying 'Preparing battlefield' or something like that.