There really isn't a more in depth and tactical way of combat than turn based unfortunately.
A couple you might want to try, maybe you'll get the hang of it (or not, still interesting ones):
Gateway to the Savage frontier
- a later Goldobox game. The reason I recommend this is because the fixed up the interface a little, and you don't need to play earlier titles to enjoy this one. Use the Goldbox companion to aid you.
- the LAST wizardry game. Super-imtimidating looking and complex, yet not that hard to get into. Yes, the fights get rather repetitive and drown out, but still, there's a fantastic tun-based engine in there.
Knights of the chalice
- similar combat interface as to those in the GoldBox games, but improved to the max. It's incredibly deep, yet super fun.
- super simplified tun based combat. the games are very story-centric though, and well written.
Some other great RPG games with turn based combat:
Divinity: Original Sin
Play the second one,
Drakensang: The River of Time
It's like the first one, but about a hundred times better in every aspect. It's still a flawed game, but it has a huge heart. The visuals are even more cartoony and charming, and the story is much more intimate and relatable. The whole thing is "generic" in the most self aware and heartfelt way.