Well, it could be a loose truss rod nut or loose truss rod anchor... When you relieve the tension of the strings on the truss rod the rod bends itself back straight... Then when you put new strings back on... The rod may slip, maladjusting your action... I suggest trying to string one string at a time next time... So, instead of taking off all the strings and putting all new strings back on... Take off one string and put the string on that goes in its place... leaving the other on the guitar... do one string at a time..
Jumbo fret wire and low action are synonomous with metal/shred guitar... It makes the playability of the guitar feel like butter... But when it comes to anything but metal/shred... it loses it's character. I would take my Vintage American Strat over any JEM, ESP M-II, Jackson Soloist... etc...etc... Just because I'm comfortable with it and I love the way it plays... it compliments my style perfectly... But to each his own...
