The greatest team ever is already broken... They are living in the past, which is dangerous.
I don't think a drastic overhaul is needed, yet. Just someone bold enough to make a few changes. Starting with a #9, and playing messi behind him or as rw. False 9 can still be used, but the team needs versatility. Barça don't have that anymore.
A great cm/dm to cover for Xavi/Busi is needed too. And a top cb, to give pique competiton or bench him. 2 cbs would be the ideal. But none of that will work without a brave coach.
It's not only about the players though... The directives, fans and especially the press are still living the past too...
I really can't believe how much stick has Tata received from the press from day one, mistakes aside, everything he's tried to improve the team has met strong resistance from everyone... So it's not only about being brave, because I think Tata has been, it's also about having the right conditions to do your job... Needless to say, that doesn't mean that he should be left off the hook when he screws up...
So whoever comes next, or if he continues next season, should have a proper environment, one that doesn't have every single detail questioned, and in order to do that people need to understand that the golden generation can't last forever, that La Masia can't keep producing world class talent every single season, that possession does not mean everything, that an alternative direct approach isn't a spawn from hell and so on... The club, fans and press need to look forward instead of backwards and move on, which doesn't mean disregarding values and ideas, but transforming them to fit the needs of the present...