Howdy do, Lusi-sprites.
I have always had reservations regarding mods or custom add-ons for games like World of Warcraft and this idea that many people have that certain add-ons are absolutely necessary and mandatory. Some people will simply not allow you to raid with them if you are not using customized raid frames, or add-ons like Deadly Boss Mods to hold your hand through the content. And yes, there are mods to tell you whether or not everyone else is using the desired mods.
On the one hand, it could be said that if the game designers feel that you need something in order to be successful at the game, they will provide it to you. Therefore all of the add-ons that we use are purely optional and are above and beyond what is really needed to play the game. For example, many people use mods like DBM to tell them when certain boss mechanics are being used, when to run away from the group, when to heal certain people, etc. However, all of this information is readily available to the player using the native UI. Cast bars, buffs, debuffs and raid warnings all communicate this information to the player. It is also possible to heal, focus and assist key players using the native UI. It is just more convenient, a bit easier, to let an add-on customize it and display this information in an easier to digest manner. Consider for a moment that when Blizzard invites top guilds to raid publically and competitively, they are almost always forced to raid without using add-ons. Paladins have to coordinate blessings without Pally Power, healers need to pull out their raid frames rather than use Grid, and use hotkeys instead of Healbot or Clique. Shocking, am I right?
There is a flip side to this, of course. Over the years many popular and even unpopular add-ons have made their way into the native UI. This indicates that Blizzard saw a failing in their user interface, saw the solution that users created, and incorporated it into the game. Scrolling Combat Text is a great example of this. That extremely handy mod was rendered obsolete when Blizzard fixed their darn chat boxes to not be, well, stupid. So all of the people using that or any of the other mods from which Blizzard borrowed ideas, were they taking the easy road, or were they just ahead of the curve?
Now that I am playing a healer almost exclusively, I have had to bow to popular opinion and install more mods. It is just too painful to heal without Grid and Clique. I will continue to try to avoid excessive modding, though. You never can quite tell what mods Blizzard will accept and embrace, and which they will put the boots to. Things like Grid, Healbot and Xperl Raid Frames have been around for so long that you would think Blizzard would have incorporated them into the game by now if they were ever going to. Considering that the Loatheb encounter in Naxx is a big “F U” to healers using Healbot, it seems plain that while not banned, some add-ons are seen as unnecessary and extraneous.