The only reason that BADS can walk into raids these days, are even ATTEMPTING raids that they should not be doing, is that it's extremely easy to gear a character. You can go from "fresh 85" to "fully 346 / 353 / 359 geared" in two weeks.
The reason for this IS FOR CASUAL RAIDERS (not "casual players" where people actually mean BADS, people who won't take 15 minutes to go on elitist jerks and refuse to use proper add-ons, screw up interrupts and put out mediocre DPS) to be able to keep up. It's also designed so that HARDCORE RAIDING GUILDS can quickly gear up new recruits, it makes it so that HIGHLY SKILLED PLAYERS who return to, or start, the game can quickly work on current-tier content.
NONE OF THESE DESIGNS EXIST SO SKILL-LESS, TALENT-LESS BADS CAN RAID. Raiding takes work, it takes dedication. Do you think Paragon just walks into content and 1-shots it? No, they sit there for 4+ hours wiping on the same boss, then do it again the next night. They are good BECAUSE they have put in their time to get good, to learn fights, to improve their abilities. They sit on the PTR learning fights before they even come out, so they can compete for world-first boss kills.
Players who don't ACTIVELY ATTEMPT TO IMPROVE (sitting there and playing your toon IS NOT practice and IS NOT improvement, you must actively be looking for opportunities to eek out more DPS, to time interrupts better, to move faster, to improve mana usage, etc) should not expect to beat the last boss of any current tier. Period.
Please, stop using the fact that you can get the same gear as top players as an excuse for expecting to be in the same content as top players ("but there should be an easy mode" - there is, it's called NORMAL MODE, if you can't handle it, then what you're really complaining about is that it takes wipes to complete a fight. IT SHOULD, if it wasn't a challenge it wouldn't be a boss fight)
Blizzard rightfully didn't make a months long grind just to catch up to current tier content. They did this so that guilds which lost players wouldn't be stuck going "well I guess we can't raid until next expansion, because there's no way to catch up a new player in time". They did this so people who are new, but dedicated, can get into the HEAVILY SKILL BASED raiding Blizzard was going for, over simply being stuck behind arbitrary gear requirement and unwarranted elitism.
Stop being BAD if you want to be in current tier raiding, but don't view being GEAR-ACCESSIBLE as meaning it should also cater to LOW-SKILL, that's not how a successful game works.