As a fan of one of the high payroll teams (Cubs) I'll go ahead and answer #2.
I wouldn't care one bit as long as the Cubs were winning. And given that they haven't had all that much success with high priced talent lately (Soriano, Bradley, etc.) I might almost prefer that they build from within a bit more, rather than simply trying to outspend other teams . (Good news Cubs fans - the Cubs have more of the top 100 minor league prospects than any other NL team, according to Baseball America.)
And despite the fact that ny team does spend money, I actually would like to see a salary cap, provided that they follow the example of the NHl and also have a salary floor. While I think it's silly too allow a team to spend nearly twice as much as the team with the second highest payroll, i think it's also ridiculous to let other teams spend a horribly low amount on payroll. My thought would be that you set a realistic cap, then also set a minimum payroll of perhaps 75% of that cap. That way, if you set the cap at maybe $100 million, the teams that have been historically cheap will be forced to spend $75 million.
And if some owner claims he can't make money if he has to spend that kind of money, then perhaps he should find another business to be in. Sell the team, and if a buyer who can meet the payroll can't be found, perhaps you need to drop a few teams.
The one other thing I would add to any salary cap would be a version of the NBA's "Larry Bird Rule" - that is, allow teams to go over the cap in order to keep their own free agents. I would limit it to players that had been in the league for at least 8 years, the last 5 with that particular team. Then perhaps players would be a bit more apt to stay in a city for their entire careers, rather than moving around as much as they do. Roster stability is a key to building a fan base - it's a bit more difficult to identify with a team when the rosters turn over as quickly as they do. I know that in the Cubs case, they had 6 of their 8 position players in place for about 5 or 6 straight seasons - the entire infield of Santo, Kessinger, Beckert, Banks, as well as Hundley at catcher and Billy Williams playing in either left or right. Made it a lot easier to get to know the players, rather than trying to learn 15 or so new names each season.
Great question as always.