Welcome to what many guilds encountered in BC called the "T4 rut." In BC, there were multiple guilds on every server that could not progress past T4 content due to many of their members being "casuals" and not showing up every raid, members that were showing up every time that ended up getting gear would leave the guild after gearing up and join further progressed guilds, and guild rosters being stressed because 25 mans back then was the only way to go further. Now maybe not all of this applies to today's problems, but it's something you have to live with. I will say I have been experiencing some of the same issues this tier with my raid group, and the only solution is KEEP REPLACING. Eventually, natural selection will sort out the strong from the weak, and the dedicated from the lazy .
I meant that we shouldn't want someone with greens and PvP gear, I agree that we need to recruit!
Prolly gonna catch flak for this, but I'd sooner take someone in greens that shows up every week on time then any of those 6 ppl that disappeared without warning or apparently caring. I also note that some of them are still in your guild, just not raiding with you. Have you tried asking them why ?
If turnover is an issue for you though, just require attendance, and give players that have shown up on time priority on MS upgrades. If someone shows up late or misses a raid (without arranging a suitable substitute ON THEIR OWN) knock them off the priority list til they show up for a couple raids. (anywhere from 2-4 weeks).
In the end though, you need to figure out what works for you, and more specifically, what ISNT working...