There are many viable tactical choices but they're all predicated on one thing: you have to be willing to lose guys. Every tactic against the AI that isn't preparing for the worst is a huge gamble. And the pay off just simply isn't worth losing a guy over. But if you're down with actually turning over warband members (I'm not), then sending out runners to grab wyrdstone, ambusher parties, stuff like that does work.
Some hands the game deals you can also frustrate, but, that's where tactics really shine. When you've got your guys spread to three corners of the map and one group is out gunned, that's where things start to get interesting. But also hugely risky. Going on the offensive against the AI is always just such a risk. You send two guys after one guy and find out he's got 3 friends right around the corner, who all hit the same guy when they enter combat and *splat*.
You can play safe against the AI and win but it's a little bit of drudgery if you're not a turtle type player as I am. For me the joy of Mordheim is the environment and its impact on tactical play, those times when you don't just shut your whole warband inside a house and murder the AI as it tries to get in. The warband management is ok although I still find the abilities super boring. "Builds" eventually make sense and start to shine but the game is way too stingy with benefits and cool stuff in the early game. Guys don't feel unique because they're points-built instead of randomly leveled like Mordheim Table Top. It's hard to get attached to them.
Still, I think the tension and difficulty of SP, the consequences of your actions, combined with the amazing maps and faithfulness to the source material, still makes Mordheim a game worth buying.