No offense to QT, but why the fuck did he start with his Q? Your passive gives you enough sustain and starting W allows you to ramp up DPS quickly and take camps without needing to smite.
Why is he building Bloodrazor? WW's W provides enough AS against low health targets. You should grab Cinderhulk to get tanky early so you can actually have drawn out fights (where he excels). He even admits he should have gone tanky!
Warwick's MS is so low (imo) so that his W MS feels more impactful during bloodhunt. It also encourages him to build some MS which in turn also increases his ult range (this is hardly new. Sion's health scaling is an example).
If you want to be sticky with Warwick, E when moving up, Q to get in between their escape direction, activate E to fear them in the opposite direction, and obviously AA when you can. Considering how he's encouraged to AA, I can see why his Q cost is so high (plus it also sustains him, having a low cost sustain ability on top of his passive would be obnoxious).
You build Warwick durable so he can win extended trades.