I think 486 iLevel requirement is a GREAT idea. You certainly are never forced to raid the top tier of LFR, no more than you are forced to do heroics, or to do dailies.
It'll add a nice goal for people to try to achieve, though, even if they are totally casual.
You can achieve an iLevel of 486 pretty easily nowadays - especially with item upgrades - you don't technically need daily gear at all!
(But it helps!)
I personally haven't made it past Elegon in MSV on normal. So, you definitely don't need to be a raider of any kind whatsoever to get 486+.
It's been pointed out many times already, but here it is yet again. From page 4 of this thread.
For those of you who aren't wonderful with math, here a sample breakdown of how fast you'll get geared enough to hit that 486 item level once you make the 470 item level requirement to queue into HoF/TES:
You have 16 gear slots to fill, assuming you don't have a 2h weapon.
LFR gives you about a 16% chance of winning an item, so assuming the loot you get breaks down perfectly so you get it 16% of the time and each item is something to fill another slot you need to upgrade, you'll need 96 boss kills (90 if you use a 2h weapon). That's essentially 10 weeks of HoF/TES, assuming all goes perfectly.
Now that you have 16 483 items, you'll need to get 7 of those items up to 491 to hit 486. to get those 7 upgrades, you'll need 10500 VP. If you're still only running LFR, you're getting 450 VP per week if you run all 5 parts. That's almost 24 weeks to get up to 486.
Can you now understand why Blizzard is full of crap when they tell players that you can advance through LFR through LFR alone? And that's when drops fall out right for a player. More often than not, they're duplicates of items the player has already received or share a slot with another item (ie getting off tier legs and a tier token for legs). Players will still being trying to get into HoF/TES when Thunder King comes out, and still wont' even be close to geared for Thunder King when the raid after that comes out.
They're locked out of content despite Blizzard's assurances that they won't need to participate in other content to progress.
Think about it - buying a new item usually yields a 13 to 26 point item upgrade for as little as 1250 VP if you do dailies. VP upgrades only yield 8 points for 1500 VP.
Blizzard is obviously trying to force players out of raiding and into dailies for gear. They need to stop wasting time, stop developing raid content and just make everything dailies.
So no, you can't easily get to 486 with upgrades.