One thing that would work is making Free Accs getting access to the torch item in a more reasonable way. Frankly, if they can help anyway, why Cipsoft can't make a NPC in Free Acc areas that would give the torch to them?
A simple way of correcting excessive rewards to Free Acc players would be simply inserting a minimum level required for Free Accs chars and also giving to these players a low and symbolic reward. We would have more public willing to do something for the server. Not to mention retired people that want some charms and need a torch to get it. World Quests should involve the whole server and I don't see why Free Accs can't really help in an efficient way.
Other than that, I would be ok with Basin expansions happening on easy to access areas, specially the Free Account ones but ONLY if we get a way more meaningful reward from completing the event. And yes, I really think that we need much better rewards to High Level players. That's something that it is definitely missing.
One last thing would be chance to get some sort of random prize out of it if you light all basins and possibly some new ones to be inserted, I think that it would stimulate people on having multiple characters helping out on it... But that's just my two cents.