I'm diehard AC Milan fan.
I would say Kaka is one of the best playmakers in the world during 2004-2009 periods.He was a complete playmaker fast,strong,elegance,great passing skills and shooting skills.
Howewer he was a player that could be shine brightest only when his body conditioning was completely 100 percents,since his playing styles relied a lot on physical attributes like pace,body balance and accleration.If you had seen a lot of Milan games his peak periods,you would have seen when he wasn't in his best conditions or fitness he played like nothing or even terribly especially a lot of Sirie A games that sometimes made me mad a lot.I'm still sure that if he had performed more consitency and not used too much his athleticism in his game in league ,we would have won more than 1 league title for sure.
When he was in perfect conditions or fully fit,like I have said before in the first paragraph.He was so unstoppable...possibly one of the best performances from CAM/SS positions in this era.
He was so impressive in a lot of UCL campaigns like 2004/2005,2005/2006,2006/2007(god level) but in the league campagins compared him with Totti,Ronaldinho or even Henry,I would honestly from diehard Milan fanboy that his performances in league was inferior to all of them(still great but not as great as others think),the things that upgrade his status to one of the best players in the world,like I have said,
UCL
I can see his flaws
1.He was a footballer that relied a lot on athleticism (that effect him in later stages) to bring his best form.
2.His league consistency wasn't great enough to be called"I'm the best in the world"(espcially 2006/2007)
3.Anchelotti used him too much especially last two seasons with Milan.
4.He played too much direct sometimes and wanted a bit of specific system that can supported his potentials and abilities(Anchelotti's system).I couldn't think posession football system could bring out of his best forms.He was most suitable in direct,fast and pacey system/tactics.He wasn't a player that can suitable in every tactics.
In fact, he played really well in league system but he could have been even greater,if he was more consistency especially in 2006/2007 seasons(his best form in UCL) that some of his league matches performances in this seasons can be even called "mediocre".
AC Milan places in Sirie A.
2003/2004 1st
2004/2005 2nd
2005/2006 3rd
2006/2007 4th
2007/2008 5th
2008/2009 3rd
League rankings can tell somethings about that squad.
I will tell some important players details
Dida-too much inconsistent and error prones
Maldini-after 2004/2005 Maldini had a hard time to dealt with knee injuries plus with his age he couldn't played in every league matches.
Nesta-injury prone especially after 2006
Seedorf,Pirlo and Gattuso-three of them were the most consistency players of that Anchelotti's era.
Sheva-
in 2003 he scored only 5 goals in league,he was a bit like Kaka,played better in tournaments(UCL)
Kaka-The superstar on this team but sometimes not consistency in league system plus he was a player born for tournament football that didn't played frequently(like UCL) not the tournament that need consistency like 38matches Sirie-A.
Another reason for this Milan have won only 1 title is their squad was more suitable in tournament football not 34/38matches system and Anchelotti and their squad was about more focused on UCL campaigns.
If I rate him,I will rate him like this
league system:he played really well but sometimes a lot of inconsistency forms,so I will give him 7/10
UCL:His favourite tournament but if you look neatly,you will see he played really well in 3seasons
2004/2005-great
2005/2006-very great
2006/2007-god level performances
Other than that:not mediocre but not excellent as well
I will give 8/10.
His best performances in my opinion(only in UCL)
In fact even his peak I rated him as inferior to peak Ronaldinho, peak Rivaldo or even peak Henry can be considered better(but I love him the most).
In 2006/2007 he can be considered as the best players in the world(I consider him as the best).
He is one of the most my favourite players ever.
From Diehard Milan fanboy.