I'm actually one of the few people happy about the change...
I travel solo and I eat very little, so it's unfortunate that most waitstaff at restaurants do not care for people like me and we're not always provided with stellar service. It doesn't help that I look very young. My poor waitress sees someone who appears to be a teenaged girl come in and order a Coke and a small salad, and there's an automatic (and natural) assumption that the tip is going to be very poor. Now, I'm a New Yawker and I've also spent my fair share of pre-disabled days waitressing, and it's anathama to me to leave less than 20% or $5 on the table, whichever is higher. If my check was less than ten dollars to begin with, my server would ordinarily end up with a buck and change as a tip and I don't think that's fair considering he or she had to bring me the same bread basket and the same drink and the same dish and stop by the table the same number of times as somebody who'd ordered the lobster and a bottle of '89 Stags Leap merlot. So I don't necessarily base my tip on a percentage of the total amount, not if that total is insanely low. That being said, the server has absolutely no way to know this about me. I do not blame anyone the slightest bit for seeing a teen girl come in and wincing, with the assumption that I'm going order everything on the side, drink glass after glass of free ice water with lemon, send you back to the kitchen eight times for ketchup or clarified butter, and then leave two dollars on the table because my check was $12. As I said, I've been a waitress before and I know that 9 times out of 10, that's what happens when somebody who looks like me and eats the way I do is seated in your section. Most servers will grin and bear it, and this is especially true at Disney where everybody is smiling and helpful regardless of the customer's estimated tipping potential, but there are always going to be bad experiences with servers who immediately write me off as a loss and can't be bothered to come to the table without acting like I'm some kind of cheap n'er-do-well who is a big waste of time. Even if that never happened, it still makes me feel bad to know darn well that my poor server is going out of her way to bring me the extra sauce when she "knows" her tip won't even be enough to cover the tax on a meal. I sit there and I want to tap her on the shoulder and say, "Don't worry, I know how much your job bites, I'm not going to leave you hanging!" Only I can't do that, obviously, so she gets to spend a depressing hour waiting on me and only discover at the very end when I leave the table that it was worth it. Now, a nice surprise is always a fun thing, but personally I don't think it makes up for the disappointment that inevitably comes when the hostess seats a party of teenage girls in your section.
Maybe it's just me. In any case, the fact that my server knows he or she is getting at least that 18% cuts down on my guilt factor, and also increases my enjoyment of the meal because I'm not worried about sending something back to the kitchen if it's unsatisfactory, or requesting extra honey mustard, or getting the evil eye when I order that ice water and lemon. I can do those things without the constant self-conscious fear that my server thinks I'm a high-maintenance pain in the posterior who won't tip.
This is probably a unique point of view, mind you!