There is no hard mode in vMA, unless by "hard mode", you mean vMA vs. nMA.
Weapons only drop in vMA. They do not drop in nMA.
The chance of getting a specific type of staff (e.g., a sharp fire staff) is 1-in-144 per run. It's extremely low and it's not uncommon to find someone who's run vMA hundreds of times and never gotten it. You might get very lucky and get it within the first few runs, but you should not go in with that expectation, and you should not get your heart too set on a build that requires a vMA staff.
Do vMA for the challenge that it presents and for the player progression that it offers. Don't do vMA expecting to get a weapon, as that will likely be even more rage-inducing than the arena itself.