When I fought Ygerna (on nightmare) I summoned my creature right away (which I probably didn't need to do, though he did keep Behrlihn occupied), cast WotR, by which time she was right up to me, so I cast Splitting Arrows, jumped back and IIRC only needed one regular arrow to finish her off.
If I decide to try a pure warrior build, I can always invest in Intelligence and Spirit rather than learn Mana Efficiency, and use more Healing Auras on jewellery, rather than the Healing spell (I ended up with plenty of malachite gems in DKS, so I really didn't need to hoard them).
