As I said, there is no expectation whatsoever for rouletters to play to the same level of veterans or premades. The important part is that they try and don't just outright dismiss FL as 'it doesn't matter' purely because they themselves have little/no interest in it. All this does is promote the notion that no effort or care is required purely because 'its only FL', hence leading to the many issues faced within FL at the moment. Too many will sit aside and just AFK. If someone attempts to lead in the hope of keeping the team together and maintaining coordination, too often are they faced with people actively and maliciously trying to make that harder (removing markers etc.) or responding with rude, sometimes bordering on abusive, comments. Just try!
As I've said before and I'm sure many FL regulars will agree, if I was paid for every time I heard "Who cares? I'm only here for the exp", I'd never have to work again.
Unfortunately, the structure of FL doesn't lend itself well to a split, ranked system like CC. Requiring so many players, it's almost impossible to divide teams up by rank/experience - lower ranked games would continue with no issues, while higher ranked games would never pop. Not unless the boundaries for those 'ranks' were so wide that there wouldn't be much point to adding them in the first place. Sadly, that's one negative to the design of FL.
And I'm not remotely in favour of the "just do your own premade" attitude that some veteran players take. Casual players are less likely to want to practice if they're being destroyed over and over again or forced into the same meta classes repeatedly just to stand a chance. Some will take it as a challenge and use it to drive their motivation to practice and improve for the purpose of being able to counter a premade. Though, these are few and the majority appear to take the route of 'let them win, end it fast' all while complaining in chat about how premades should be banned.
Both sides share some fault.