I would rather have tactical battles that are sophisticated enough to be satisfying but not so sophisticated that the computer players can't fight them effectively. I think Fallen Enchantress strikes that balance.
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But in Fallen Enchantress, if I might be so bold, you can set your units to auto-play and know that the computer players will play it competently. Maybe not as good as an expert player but well into that "good enough" realm for most players.
Playing out the tactical battle should give some advantage to the human player vs. autoplay. But it shouldn't take an obvious defeat and turn it into a victory. It should be more of a tilting the tide.
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In other words, the complexity of the tactical battles shouldn't get ahead of the capability of the computer AI to make use of it.
Well, when you put it that way, you have me almost convinced. 
It's true the player has always more room for abuse. Maybe when it's time for an expansion, with the general AI refined thanx to the post-release work, something might be added to tactical battles too (nothing extreme, as I said, some spice).
