(Honestly, I think the leadership is new to raiding in general, and don't realize that most guilds believe paladins are supposed to stay at the back. And we paladins are not enlightening them. :) )
Getting to melee makes Molten Core so much more fun! I find healing and cleansing can easily be done from the front lines. There are times when it's better to stay back (for example, when I need to help keep the main tank up), but the guild leaves the choice up to the individual paladin. This is actually quite liberating. I find that having the option to melee makes the game more fun, even if I choose not to take it.
Now, I'm not sure that paladins meleeing is the absolute optimal strategy. We are only on Gehennas. However, we have problems getting more than 30 people in the raid, and we did take down Magmadar for the first time with only 33 people. That seems like a pretty good accomplishment, so I'm willing to reserve judgement. And I'm having a lot more fun, so that has to count for something.
In all honesty, I think a lot of the problems at the raid level, from loot issues to class behaviour stem from the arrogance of some raiders. A lot of them believe that they know how to play your character better than you do. That's why they impose restrictions on you and on themselves. They do not trust you to make the correct decisions for your character, and so they try to make the decisions for you.
A good guild, in my opinion, needs to adopt the view that: The person who can best play your character is you. In the end, it all comes down to trust. If you trust that your people know how to play, you trust that they will only take loot they will use well.
There's a quote I've always liked. It's possibly a bit extreme for something as mundane as guilds in an MMO, but for what it's worth:
"You? I know you! You trust beyond reason."
She met his eyes steadily. "Yes. It's how I get results beyond hope.'"
- A Civil Campaign, Lois McMaster Bujold