Hi and welcome!
The "worst" stat configuration that one can have is 6, 8 and then rest 10+ (in other words... maximum of one below 8 and another below 10). It's a fixed rule with no exceptions being made (and also remember that it's the ability scores after subrace modifiers!).
8 is already a very low score where 10 is the average for a human population. In terms of strength, 8 can probably be considered being the strength of a 12-year-old "normal human child"... A score of 6 is so extremely low that it's kind of difficult to imagine it in real life when applied to a human being (6-year-old child?). So... erh... crippling a third stat below 10 is kind of... um... tricky... as one is approaching the inability to have a functional character.
A character with the same physics as Raistlin should be quite possible to create! I can't remember his exact ability scores... but I would imagine it being like:
9 str... 8 con... superb int... high dex... high cha... dunno about wis... average to high?