Every player, agent, lawyer, club is different. So comparing one team/player to another is irrelevant. The maths are different and each stakeholder will have a different view of the maths/value of each piece of negotiations structure.
This will include basic salary, bonuses for a range of matches, image rights for a whole host of commercial activity, options of further years, sell on values, shirt sales, number of TV appearances/interviews, time off, use of private medical facilities vs those at Carrington....there are loads of things.
I was once told that Paul Scholes contract was held up for ages because he refused to do TV interviews but it was in the SKY contract with PL clubs. That took ages to sort out, but because it was all behind the scenes no-one heard about it.
I don't know what extras need to be discussed. But clearly they do.
On a different question...why is everyone worried?