So far I've found that Lore of LIfe and Lore of shadows work well with my slann. The lore of metal does seem kinda situational. The enchanted blades spell works well, and final transmutation isnt terrible, there are just so many other things/combos that work so much better. Especially with the combination of "Enfeebling Foe" from shadows and "Dwellers Below" from life. The only problem I seem to have so far are armies that take massive numbers of small units. They are kinda hard to track down, and since I dont have any magic missles, or alot of shooting, it becomes a problem. Then again, lizards seem to always have had that disadvantage.