It has to do with how they decided to implement cross server queuing in this game. For example, in WoW, the game wasn't BUILT with cross server in mind initially, it was an after thought. Because of this, when they implemented it, people are basically joining the "host" server for content (think about the same way that games like COD and Halo work). In this game, however it is different. They have separate servers specifically for instances... call it... a design feature, while also having a flaw.

Because of this, that is why there are timers attached to the instances, and that is why they are very specific on what you join up for and such, because each instance is segregated to their own sections on the servers.

As such, it isn't an "easy" process to have you just randomly run into an instance, because they have to reserve a full instance space on that server just for you. If 50 people decided they wanted to "solo" a dungeon, you are potentially keeping 150 people from being able to run content. Don't believe me on this one, get to 50 and then queue for Amdapor Keep. Takes 5 minutes (even as a DPS) to find a party, but then another 30minutes or MORE to reserve and instance.

The flaw here, is that you will likely never get your request fulfilled because of the way the system was designed from the start. It was a calculated business decision. With having level sync, you still have the option to enjoy the content no matter what your level is, you are just going to have to enjoy the content the way THEY want you to enjoy it. I'm sorry.

And I am not against you here on this. I enjoyed trying to do group content solo when I played those other games... so it would be a nice "feature"... but overall I feel this is better for the game, since it prevents content from no longer being enjoyed as it was INTENDED. 5 years from now, if you want to go back and do BCoB (the current raid), you will be able to do it at roughly the same difficulty that it will be today. Oh how I wish I could go into wow today, get together 40 people and run Molten Core, or Naxx, or the Back Temple, with the same difficulty level and enjoyment that they were designed at 6 years ago. Instead, I could solo Molten Core at 80... different type of fun... but still completely NOT the same.