You guys are missing the point. You are asking people to do raids and grind to get gear yes? Well if there are no people doing those raids, there is no way to catch up. If there are no opportunities to level up in gear and knowledge, there will be a huge divide and its already happening now.
The point you missed is that there are players still doing these raids. In TBC there always are because it's required to get to T6.
The problem I sense with you is that you're wanting it to fall in your lap at a point in the game where your options are limited. First off, go find a guild to join. There are so many that need mages. So many recruiting during T6 as well. And then go find out when people are actually running T5 raids because most of them are semi-guild runs. Talk to people. Go do a Who search for T5 raids and ask them. Or go do some PvP and leave global open, they pop up if you're patient. Like seriously man T6 attunement is literally clearing SSC and TK one single time each. So go do that. My guild has looked for a mage for a month and if there was a T6 attuned one we would funnel you all the gear. Guilds are desperate for players.