Here is a gauge for AK. It applies to DD only since the demon wall is a timed damage check. You can monitor your DPS off of the first boss in that dungeon.
If, on the first boss, you kill the priest later than 5 seconds after the spawned soulflayer summons the first small rock golem, you can still beat the demon wall in time, but you will struggle, and you will have to kill the bees with a limit break.
If you are killing the priest earlier than five seconds before the soulflayer spawns the rock golem, then you might be able to have the tank hold hate on the bees and just zerg the wall (depending on your tank). You will have no problem beating the dungeon.
Demon Wall has a soft enrage of 3.9 minutes. That's how long before you are pushed into the void zone and can't move back out. Demon Wall himself has ~24k health, and the bees each ~1.6k. FFXIV App gives me damage-taken values in that ballpark, although I've been unable to accurately confirm the exact value. 3.9 minutes, or 234 seconds into the fight, puts you into the 6th repel that forces you into the void for good. Assuming you kill everything, your group only has to average, rounding up to be conservative, 120 dps until his soft enrage to beat the encounter.
People were lied to early on, a lie that is perpetuated still today even though we all know better. Demon Wall is a PAY ATTENTION! - endurance race, not a DPS race. Unless people are not planning the fight properly or are getting knocked off, there is more than plenty of time to kill Demon Wall before you are forced to wipe. The average fresh-geared DPS will do ~70 dps in AF + GC weapon, so two plus tank DPS is sufficient to down Demon Wall without going crazy trying to get full 55+ gear level in every slot. This is before considering any limit breaks as well, which give you even more DPS latitude.
Gear certainly makes the fight easier, as it does with all fights, but as long as you game the mechanics well, DPS is one of the lower concerns of that fight. My advice is to get used to the mechanics, and don't worry about gear much past AF and GC. Your upgrades are in AK, and as long as you play smartly and well, you'll have no problem with any boss. There's no substitute for experience though. You need to get in there and get pulls in on bosses. No amount of guides or videos are a substitute, Shuonz. Knowing your class's cooldowns and how to keep yourself alive is a necessary added bonus, and well worth looking into for any dungeon.
If you are in full af and ilvl50 accessories and weapons just do WP, AK will end up being a pain in the butt drag on forever and if you are using DF unfair to the people dragging you to the end.
As one of the many, many people who tank AK daily with people in that gear or less with little to no problem, I can flat-out tell you that you are 100% false. I have more problems with people in better gear, since for whatever reason, they think their gear gives them an invitation to start ignoring critical mechanics.
wait.. im getting mixed responses... so if i turn uo in a DF group in WP as a healer in an ifrit weapon, DL belt, legs, neck, ring and bracelet, am i cut for speed run, since that is what everyone is doing?
My first response is for dungeon finder, or people just looking to fill groups to queue AK with. For speed runs, you'll need a higher gear level. Assume a mix of AK+DL gear and your relic weapon. Since speed runs are built for, well, speed, you'll need a higher standard of gear if you wish to contribute. Speed clears and normal dungeon farming are two different animals, though.