I think the Kingdom's familiar is fine as is..However, the Spy should be nerfed into the ground. The power to hit everyone on the field for 10 damage is far too strong, and even considering that most champions are within range of 10-20hp (unless you spend most of your attribute points on constitution) it can kill them with relative ease. Consider that the Spy is a very low tier summon, it's power is grossly disproportionate to it's tier.
Also, the summons seem to suffer from the same weakness as the champions, though even more so as they get hardly any bonus to damage done based on level. You also get to the point where you can deal many, many times the damage it would take to kill a targeted summon/champion, and I think that is a bit much. The Health stats of the units need to either scale up better, or the overall damage that most units do (baring the rare and powerful things such as dragons, elder demons, etc.) to allow for a more fantasy feel of trading blows.