I think this is roughly no change for his very early game, a slight nerf for his early-mid game, and a buff late. With only 500 health at lv1 (he should actually have more), 7% total health comes out to 35, which is exactly the amount he lost on the base shield. He actually has 576 health at lv1, but since the scaling got cut in half for bonus health, depending on how much hp he was getting from runes/masteries, this might actually be a slight early nerf. At lv9, supposing he maxes his shield first, he has 1156 base health, and 17% of which comes out to about 197 (282 total base shield), a net loss in base shield amount. At lv9, it breaks even with the old shield at 924 bonus health (it's only an extra 2% scaling, after all). However, already by lv10, it is almost certainly a buff. With 1242 base health at lv10, a 17% health shield gives about 211, which with the 85 base shield amount comes to about 296, only 4 points away from the old 300 base. With a mere 200 bonus health, it's already breaking even with the old shield. By lv18, when he has 2038 base health, he's getting about 346 on the shield from the base health alone, resulting in 431 base shield at lv18.