There is enough 'talent' to field 4 more teams. Usually these new teams will have to start out with fringe NHLers and aging vets until they can get themselves through some drafts, but there are enough players floating around to fill 4 more teams. If you just look at the Canes, players like Boychuk and probably Chris Terry would be good enough to play at the NHL level for a new team starting out, at least in the early years. Certainly the NHLPA would support expansion even without getting any of the expansion team fees...more revenue, more NHL jobs, all good.
If there is money to be made I'm fine with adding 2 teams to start. I'll leave it to the experts and league and owners to figure out where 2 new teams should go and what should happen after that (ie adding even more teams). Moving teams is a sore spot for me as an ex-Whalers fan, so I don't like that as an option unless there is no alternative. Quebec, Markham/Toronto, Seattle, Las Vegas, whatever makes the most sense for new teams I would be ok with.
I don't think it would dilute the overall talent base enough to make a difference to be a concern. Did anyone really watch the NHL after expansion teams were added each time and think 'the level of play across the league sucks now?' Who wouldn't love to watch Zack Boychuk score 30 goals and be -50 for the 15-60-7 Las Vegas team that first year? I fondly remember the first year Ottawa was back in the league and all of the ex-Whalers on that team.....Peter Sidorkiewicz, Jody Hull, Sly Turgeon, Norm MacIver, Brad Shaw, Jody Hull, Steve Weekes... Man was that a BAD team. But it gets better after a half dozen years....