1. Length of the game definitely does not dissuade me from buying stuff, I have a lot of "experience" type games like Firewatch, Edith Finch and Gone Home that I've played and enjoyed. However, it does dissuade me from paying full price for them unless they fall into category 2 below (and even then its a hard sell).
2. I'm much less likely to buy stuff on day one if its not a physical release; the only exception are for smaller digital titles that sell for 20 dollars or less (ex. Lumines, Celeste, Curse of the Moon), where the loss isnt as heavy. I bought Tekken 7 for full price at launch because the local Steam price was the equivalent of 35 USD. But 60 bucks for a digital copy is a no go.
3. Taking of from no. 3, a physical release is mandatory for any console title that's 30 dollars and above.
4. A multiplayer only game is essentially a no-go in 99 percent of cases. Overwatch is the only example I can think of where the game stuck with me, and even that has fallen by the wayside in favor of newer SP titles (its not even installed, iirc).
5. Price of other games: In a Steam sale environment, I'm not buying MGSV Complete for 15USD when I can get Shadow of War and Slay the Spire for the same price.
6. Likelihood of something going up on Humble Monthly: I have a 1 year sub, so Humble is a sunk cost. Though I wanted to bite on the PC version of NBA 2K18 given how low they're selling it for, it just screams bundle fodder to me.