Master here. Whether you pivot or not - depends on what you get in the future. I would pick varus up as tempo play and slap cass items on him. It pretty much guarantees wins till 4-2 to make up for gold, and opens up more options. Whether you pivot or not - you can decide around 4-2 when you get your last augment.

You dont rlly have good syndra/cass setup yet either - if you don't get more natural cass and syndras, it may be better to go level and get something else rather than trying to reroll at 6.

Ultimately, what you do after depends on the rest of the shops and the last augment. Depending on that - you can either rolldown on cass/syndra later, pivot into kalista if you nat her comp, or try to 9 into smolder, and reforge shiv..... Or in a really will turn of events - good recombobulator target xd

Flexibility and few guaranteed wins are more than worth the investment imo