How you place your stat points is entirely your choice. Just be sure to have the minimum points in the required categories to obtain your skills.
The standard setup after class change without armor, weapon or accessories should be as follows;
Dex - 17
Con - 17
Int - 0
Strength - gets all remaining stat points
You certainly can play around with the numbers and make up the difference with the appropriate accessories. However I feel by doing this you will be hurting yourself by further reducing your hit rate which a knight already lacks. Hit rate has been viewed as critical in PVP and some view it as nearly as critical in PVE.
I can certainly say that if you are lacking strength, once you are in Mondshine even with 3 rows of potions on it will be very difficult for yourself. Some of the monsters there have high defense and HP regen skills.
Just my thoughts to consider when making your decisions.
my take, feel free to correct me if i'm wrong, is that in the current environment stat build is going to be somewaht dependent on how pot heavy you want to go. given that a max STR build does maximize damage, this paired with a crit would maximize damage output.
given non-usage of crit pots, a high dex build would theoretically be the next best thing as dex does increase crit hit rate.
given no ap enhancements a dex build is the faster way to go. if you factor in crit pot especially the balance shifts to the high str build.
also unless it has changed the ratio of str to atk was 8/5. the additional advantage of a high str build is that it also will increase hp - which if memory serves works to the advantage of a hp stealer. unless i'm mistaken the hp stealer is 10% (?) of a persons hp per steal, which obviously means the more hp, the more effective the stealer will be.