Well, Diana's new W is gunna be busted.

Pretty much every other shield with %HP scaling has little to no base, and the users don't build AP in the cases where they do have %HP scaling shields.

Naut, J4, Nunu, Shen, are some of the few exceptions, and the base shield for them is 100. Not only that, but they all function essentially as tanks. Urgot (AD scaling) and Sion (AP scaling) are the only exceptions, with 150 base, however they don't get to stack a lot of their scaling damage stat, and are overall pretty immobile.

Basically, Diana's shield is going to make her tankier than Naut with all the base stat buffs she's gotten over the years (none of which are being touched), while having WAY more damage.

[40/55/70/85/100 (+30% AP)] to [30/45/60/75/90 (+30% AP)(+10% Bonus Health)], equating to 200+30% AP ---> 180+60%AP+20% bonus HP

If you thought she was a stat-check before, wait until after the update, now that it recently was also made nearly impossible to miss Q.