The argument that heroes have ruined Guild Wars has a basis in a mindset that I can really see and understand. The thought is that the addition of heroes took away any incentive to group, and that goes all the way back to the standard argument about PUGs. While I'm always open to pugging a mission if I have to, I get the downside. They can be unwieldy and unpredictable, and can take forever to get started. This applies more frequently as you approach higher-level content.
Some people simply don't want to mess with it, and to a point I can't blame them. Why bother bickering with the monk who has three hard rez spells on his bar when you can just load up Dunkoro and move on with your life? Before heroes, this wasn't an option. You could group with other players, try to solo, or take your chances with henchmen.
Not to disparage our old friends too much, but taking your chances with henchmen was often a lot dicier than finding a human group. The AI -- which has since been improved -- wasn't always reliable, and Lina was really obnoxious. When forced to choose between henchmen and PUGs, players chose PUGs fairly often.
This all changed with the arrival of heroes. "Wait a minute. So these things have max armor, whatever skill, runes and weapons I choose, and they won't give me any lip? Where do I sign up?" It was like an easy button for gameplay, and you didn't even have to mess with those pesky "other people" to get it done.
But aren't other people kind of the point? This is an MMO, right? That segment of players who actually enjoyed pugging felt like there was a sharp drop in the number of available groups, thanks to the addition of heroes. Why play an MMO if you're going to treat it like a single-player game? Providing every player with a nice, obedient AI to take the place of humans seemed completely counterproductive to everything that the MMO genre is about. They felt very seriously that heroes ruined Guild Wars because of this, and I really can see why they feel this way.
There's another side to this coin, though, and it warrants just as much of a look because it's just as valid. In an ideal world we'd log in, LFG to kill Varesh, find seven perfect players to join up, and go do it. Since that is a fairly rare occurrence, we've got to look elsewhere for options.
Heroes are a nice human substitute in a pinch, far better than wasting a half hour in an outpost trying to find a minion master or a resto rit or whatever your group happens to be in need of. You're logged in to play, so why not just find out who in the group has a decently geared Xandra and get started?
The other part of all this is that the concept of an MMO is very simple on paper. Provide this beautiful virtual amusement park, give an overarching story that allows all of the players to work on similar goals, turn them loose, and let them have fun together. It's when you add the people that things get complicated. With so many different people and so many different styles of play, it's harder than you would think to match them up.
This guy over here hasn't been playing very long, so he doesn't understand the mission and wants to go slow. That second guy is doing the mission for the fourth time trying to get the bonus and he doesn't want to mess around, he just wants to hurry and get done. This girl wants to wait for her friend. The next guy to join the group only has 30 minutes to play, but you can't leave until you find a healer.
And this guy over here by himself? He loves Guild Wars, but just wants to hero up and go do his own thing. It's nothing against you, and he doesn't deserve to be shuttled off to a single-player game, it's just the way he likes to play. There are a lot of players like him, and their way of playing is just as valid as his.
Heroes can be a bit of a frustration for those who are always looking for the "multiplayer" part of an MMO. I'm a highly social player who will choose humans over any sort of AI every chance I get, and I've never noticed a problem getting a group because of heroes.
I've said many times, with various phrasing, that the game is what you make it. Figure out what kind of player you are, and set out to make Tyria the kind of place you like for yourself. If you're a fan of hero/hench, you're golden. Love the adventure of finding a PUG? Figure out which district is the busiest during your play time and hang out there -- keep an eye on the Zaishen bounties for even better luck.
Do you want a solid group to spend time with whenever you log in? There are so many active guilds and alliances out there, so spend some time shopping around and find one that works for you.
In the end, it seems that heroes haven't ruined the game unless you make that decision for yourself, but I'd love to hear your thoughts, so hit the button and tell me what you think.