He may have a lot of talent, but he doesnt have the concentration and temperament of Younus khan, which is also very important trait for a test batsman. His average is inflated by three hundreds against Bangladesh. Other than that he has struggled so far specially against us he is yet to play any meaningful innings.
I will be surprised if he surpasses YK in tests. He is already almost 27 and with amount of cricket SL play getting to 30 hundreds and 10k would be very very difficult. He will be end up having very decent test career but surpassing YK will take some serious doing.
On a personal note I rate him ahead of Angelo, Chandimal will surely end up with a better career than him.