- Sustain
- Get out of CC
- Turret siege
Additionally, AP champions have been powerful in all seasons before Banshee's Veil was made into an AP item. AP champions also had much greater access to spell vamp in previous seasons and simply did not build it, so sustain is much less important to mage players than it is to assassins and marksmen.
Itemization against AP is more effective - This is both accurate and inaccurate, so I will instead get annoyed with the way you've presented your (accurate) point while seeming to include the inaccurate way as well.
If, by "itemization against magic damage is more effective than itemization against physical damage", you mean when you look SOLELY at the items typically built by MID LANERS, then you are absolutely correct.
If, instead, you mean what you said, which is "itemization against magic damage is more effective than itemization against physical damage", then you are absolutely wrong.
are all fantastic. If you want to argue that itemization against magic damage is better, just look at how often
is built compared to
.
This is important. Laners are constantly arguing about laning phase on the boards, but Riot has to make changes based on the entire game, not just the laning phase. Yes, AD assassins are very powerful when you fight with fewer items and gold against a single AP mage in a situation where the AP mage is artificially disincentivized for leaving the area entirely. However, the game is not entirely based on the laning phase.
After lanes are over, mages will have tanks and divers surrounding them. They will have supports healing them and peeling for them. And most importantly, they can just flash away after you burn your combo on them, and then they can base and move on with their lives.
Meanwhile, against the enemy team as a whole, the mage has the advantage of range and AOE damage. It is easier for a mage to land their skills and they are less likely to die for doing so. Mages can soften up the enemy team from a range, and can follow up a vanguard's initiation with a giant blast that hits 3+ enemy champions while the vanguard holds them in place with AOE CC.
Now, you as players may feel this is not as relevant as the power of mid lane, but Riot doesn't care about player perception as much as they care about the reality of the game.
Scaling - The trade off between scaling and bases is definitely one of strangest levers to balance AP champions that Riot has at their disposal. I do think it might be more beneficial to the game if scaling was a bit more standardized like it is in AD champions.