User blog comment:JmLyan/CCC2, Asalyn, the Archmage/@comment-5663427-20140530162307/@comment-7481207-20140531091839

Both build paths ("max one" vs "split ranks evenly") has clear disadvantages. Maxing one means you can only do one thing without your ultimate, most likely losing the utility of Imprisonment in favor of damage. And splitting evenly means you basically don't have a passive, and you gain less extra ranks from your ultimate. The passive also is mostly the ability to tank further than rank 5, the bonus effect at max rank is a compensation for having no other (or weak other spells and a weaker ultimate). Putting only one point in the ultimate only gives you to level 6 abilities and one level 5, while leaving your ultimate at a higher cooldown and without the extra ranks. Differences in basic abilities for every rank above 5 is also considerably lower than earlier ranks (usually half as much), so that extra 6th rank does quite little. Either way, the free stats seem to be a primary concern, so those will get nerfed.