The "unable to ever catch up" worries me as well, especially with the Valor system being as it is. If someone was on hiatus (a lot of people were since Cata), and comes in at 5.2, he should have a chance to catch up. Even if he's online 10 hours per day 6 days a week, he can farm himself to full 471 blues, get 496 head and gloves crafted, get perhaps an epic or 3 from LFR, and is then stuck. He is not ready for 5.2 raiding, but has nothing to do but waiting for LFR to reset and hope he gets a few more epics for several weeks.
In the meantime, he's probably spending his valor to buy a few 496 items to bump up his ilvl as much as he can, valor which others spent to upgrade their 5.2 drops. So if he finally gets to the level where he can join 5.2 raids, he will still always be behind, because he then only starts to farm his valor to upgrade 5.2 drops.
Of course you can tell him to raid MSV/HoF for gear. That might be nice on some of the biggest servers. On my server we have problems keeping 4-5 guilds running for 10 man content. There just is not enough playerbase to support lower tier raiding guilds on most servers.
If Blizzard really wants lower tier raiding guilds to work, they really need to merge a lot of servers before that becomes anywhere close to viable.