Then if crit costs "more" on itemization compared to hit, it could be worth to trade BoP for ff or Iis? (though it would have to be twice as costly, so maybe not...)
I've been operating under BoP being a very good talent due to freeing up many item budget points for a "low" talent point cost. Is this still true?
Hit is ~26 per %, crit is ~45 per %. BoP is still more rating points / talent point than any of the +crit talents (with the exception of Moonkin form/Natures Majesty, of course). There may be situations where, because of the gear you have, it could be worth dropping a point in BoP compared to picking up the crit talents.
Your argument works for haste compared to crit though, as Haste is ~32 per %. Erdluf has shown in the other thread (->) that the haste from talents is worth more than actual haste rating though, so it'll depend on your gear level as to which is more beneficial I think.