What was Riot's intention with making Urgot's W AP scale?

pretty much to make not a adc overpowered with an ad scaling shield. I mean, imagine if caitlyns w would scale on ad? it would do tons of dot, and marksmen are supposed to deal damage mostly with autoattacks. The only thing that they would need to make is, that urgots q applies on hit effects, so maybe, maybe, making ap urgot viable, and his shield more worth.

Throwback from yonder early days when "all" champions' abilities scaled with AP and AD items were for auto-attacks only. See also: old AP Yi.

Three reasons:

1. As Jeddite said, it's a throwback from when all abilities scaled with AP.

2. What Kawaii said, but with one clarification: It reduces snowball. If you give an adc an AD scaling shield, and they get ahead, they become invincible. Like draven if he gets super fed and an early BT, he just lifesteals through everything. Making it AP allows them to give it a higher base.

3. So that it doesn't feel as bad to buy triforce. This is why they've kept AP ratios on Ez and corki's spells, for example. Because if you buy that early sheen, but can't make use of the AP, it just kinda sucks. At least this way you get something from it.