On the touts point - touts would pretty much be gone.
Its pretty much guaranteed the new stadium will have card entry like at City's ground. Can't make the match? Ring the club and they can remove the game from your card and refund a % (say 85%). The club can then sell that seat to anyone (even someone walking up 10 mins before the game) at face value, so why would there be any need to even look at a tout?
The walk-up factor will play a good part in selling the empty seats we may encounter. A lot of people can't be arsed with the current struggle for tickets (its not much of a struggle to me - but it is to some). If tickets were available to buy on the day, I'm pretty sure you'd get people sitting around with nothing else to do and nip down to go the game.
The price of the tickets will also determine how many come through the door. With a 60k stadium you'd probably see price rises in line with what Arsenal have done (~£35 two seasons left at Library, then ~£42 last season at Library, now ~£50 at new ground). Hopefully the extra 20k seats could offset the need for drastic ticket price rises, which is the one major fear I have with the Americans coming in. I can just about afford £600 for my season ticket now, if it went closer to £1000 I would have to start selling myself!