Yes, it was necessary to limit summoning, but that was over the top. I think there are two armies where you can really see how severe it was. Death and Seraphon.
If I had to point at two units hit most severely by the rules of 1 and the limit of summoning I'd say Nagash and Kroak.
I like your idea with the restoring. It would still be less powerful than with Death (where not only wizards can do it but some units do it themselves IIRC) but more along the lines of what I would expect. Point cost for new ones, repleneshing only costs one spell.
That would also mitigate some of the severe impact of the rules of one. Because if you cannot cast Mystic shield or Arcane Bolt and have spells left you can just replenish some units.
I still think that they should change the wording of that rule of wone to "a spell can only be
cast once" instead of "a spell can only
attempted once". If it is so important for him and he rolls bad, why not let Kroak try four times to cast his mystic shield or something.
Or at least give us (the army with the best casters) an allegiance ability to disable that rule. THAT would be unique
