Tactician is not only beefed up stats. The mobs also have more skills and perhaps more ap in some cases (?) and some idiosyncrasies. The turtles for example explode in fire if killed in Tactician. Cost me three of my party.
By and large I don't find it very balanced. Classic is a bit on the easy side while Tactician should be renamed "Burden and Fear". I restarted on Classic after some time because while Tactician can be fun in many fights, in some I can imagine it as extremely frustrating.
My only wish were a mod which allows you to change between Classic and Tactician. You can change to Tactician from Classic during campaign but you cannot go back of course.