Why should TB be more challenging or more tactical? In my experience, most TB games are rather simple. In the first hours of gameplay it might be interessting to figure out the machanisms, but later it becomes rather simple and boring. What good is micromanagement, if you have several options, but only one (or maybe two) is the obvisious best joice? I can't see a lot of tactic in games like HOM&M, Shining Force, Fire Emblem, Final Fantasy or Fallout.
What I loved about the IE games was the possibility to prepare for battles. That was the point to think about different strategies. And many