Most blackjack card counting strategies are no more difficult with a higher number of decks. Instead of counting actual 'cards', one instead keeps a running total of points based on the cards that come out.
In fact a higher number of decks can improve one's advantage when counting because when the count turns in your favor it can happen with more of the deck left to come (so a longer period of advantageous play)
That's nonsensical. The EV of an hour would depend far more on the table limit than any other factor. If I could find a table that would let me vary the bet from $1 to $10,000 a hand on a two deck game they could have Parkinson's patients with oven mitts on shuffling with chopsticks for all I care.
In fact a higher number of decks can improve one's advantage when counting because when the count turns in your favor it can happen with more of the deck left to come (so a longer period of advantageous play)
http://en.wikipedia.org/wiki/Card_counting