What's too much? The weapons is a longsword BTW if anyone thinks that would make any difference is scores.
Well, as a hard upper limit I'd say more than two at 19 and one at 10 is 'too much', since you'd be exceeding the most powerful sword possible in the standard rules.
Give the sword an intelligence comparable to its abilities. If you want to create a sword with 4 lesser and 3 greater abilities, its attributes should match. Keep in mind that swords of that power are practically artifact level in power. Getting a full 7 abilities is probably worth an additional 90,000 g.p. above its value as a magical weapon and another 60,000 or more if it also has a special purpose. Intelligent weapons are just about the most powerful items in the game, and IMO the most powerful ones should be treated as legendary campaign artifacts and bring with them various drawbacks.
Another thing to keep in mind is that effectively the weapons stats are drawbacks for the player. The more intelligent, wise, and charismatic the sword is the more it wants to get its way all the time and the more it will struggle with the player for control. A sword with two 19's and a 10 for stats will try to control the character all the time. A typical +5 weapon with two 19's and a 10 for stats is going to have an EGO of 28, which means you have to pass a DC 28 Will save in order to not act as essentially the sword's minion and be dominated by them. For sword's with a special purpose or particularly extreme personalities, this is going to be a severe problem for the player.
The other thing to keep in mind is that sword's with personalities can be real headaches for you as the DM. If the sword has a personality, then essentially you've added an additional NPC to the party that is always present. You'll need to be prepared to role-play the sword at all times.
My advice would be to keep in mind just how poweful the greater items really are and limit just how mighty you make the weapon. A weapon with reduced modes of communication and more limited ego is easier on both the player and the DM. If this is your first time dealing with an intelligent item, I'd suggest not going to more than two 13's and one 10 for attributes so as to limit the sword to 'empathy'. A sword with 'empathy' only you don't need to roleplay. Instead, you just inform the player that they detect certain feelings and desires from the sword. Such weapons will have fairly limited egos, and the player won't be continually struggling for control of his character.