Why Not Give Mages better AP Scalings, Utility AP Scalings, and Nerf Base Damage?

I mean, if mages had higher AP scalings in general, and if their utilities scaled based on AP, this means they not only could not go support efficiently but could in turn be balanced for mid lane.

My mid laners are Brand, Vel'Koz, Malzahar, Xerath and Lux. Out of these 3 have seen nerfs due to being played as support, which is incredibly unfair. Instead of that, I feel if we buffed mage AP ratios by a little, making buying their items more valuable to them, and nerfed their base damages, meaning building tanky/support items was no longer as valuable. This would fix these problems.

Let's take Brand and Vel'Koz, lower the base damages on their kits but especially their passives, buff their AP scalings and add AP scalings to their passives. What this would do, is if a Brand or Vel'Koz still wanted to support they could, but they would be sacrificing some of their damage and would scale more slowly as they don't get as much gold and typically must buy 1-2 support items at minimum.

These tunings don't have to be massive, if Brand, Vel'Koz, Malz, Ziggs, etc are still viable in support whatever. But they shouldn't be consistently better than a huge number of dedicated supports in the support role so that they get nerfed for their primary role in mid. Nor should a mage with a vision item, a support item and boots be doing enough damage in a single combo to kill 1-3 people. The tuning would just have to be enough to make buying AP valuable, and not buying AP a stronger penalty.

On the topic of pure utilities. It could be possible to make things like CC duration and such scale with AP, Riot did this with supports which is... weird since they don't buy much if any AP. It would make more sense if Malz utility scaled with buying tons of AP than Nami or Lulu.