Can go Scorch instead of gathering power

Seraphs (AA staff, the tear item) can be a good item on him, I just don't go mana mythic, my love for hextech belt mobility and stats, -- not much can come close, its all personal though. Hextech just fun to use, can escape, can chase, can roam, good stats. Hextech>Rod of Ages. Rod of Ages is such a wonderful item though, hope they buff it once more!

Can go Red tree+sorcery minor tree. Prefer Sorcery(arcane comet) and Biscuits/Magic boots (scaling purposes and biscuits to survive lane, dont have to buy boots 1).

Can go attack speed minor rune instead of AP+AP+Magic Resist(or hp/lvl).

Teleport is okay but True damage on ignite combined with ult is so good.

Usually ban Ekko or Sylas or Amumu (amumu stomps teamfights).

AP Cho'gath has a lot of counters and annoying things to deal with, flash really counters your Q, if you are worried about them flashing or dashing away then W(silence) before they can do so.

Maxing W can be viable, having Q at level 2 when you're level 3 can be viable to last hit minions against someone who is punishing you in lane early on.

Many people start E for melee trades, that is ok.

Q start is best for invades, best for early CS, best for long range poke.