I'll just say this, about relationships in general; Its nobody's job to fix or complete you. You shouldn't pair with someone because they "fix" your weaknesses. Your partner should compliment you. You should try your hardest to be a complete person, on your own.
Going to therapy and fixing your issues, separate from partner, is essential. Unloading all your insecurities and weaknesses on someone is just disastrous. Sounds like simple advice but people do it all the time, hopping from one person to the next because it makes them feel good to be validated in their current state. "Why improve when this next person accepts me for who I am?".
Specifically about INTP/ENTJ pairings, I think, at their cores INTPs and ENTJs are both very independent and want freedom. So, in a sense it can be about what they "are not" , instead of what they are; We don't get in each others way. Not to mention our natural chemistry.
Never been in a relationship with one, so, grain of salt and all that.