well I do believe that price should be factored in. I mean if you mine a million doges in like say an 1hr due to low difficulty but the btc price of it is only .003 and at the same time ltc price in btc is like 0.2 it doesn't make sense in mining doges at that time. Thats just my opinion I maybe wrong but price must have been factored in or else this formula becomes useless. Why not just mine a dieing coin it will have the lowest difficulty and claim that you made alot of money even though you cant exchange it...