I have heard from a few schools adcoms that they don't care how many ever times one has taken the GMAT. They only look for the highest score. They don't try to find out how many times one has taken the GMAT. Also no i don't think that it will be seen as persistence on one's part if I has taken the GMAT so many times...no one cares...If it gives brings you satisfaction, happiness and hope that ur chances will improve with a higher GMAT...sure go ahead.....but as I understand and also have seen others say...that there is much difference between a 690 and a 730....except that yes...if one with 690 and one 730 have pretty similar profiles...yes 730 will get the pref...but if a 690 scorer has a better profile compared to one with a 730 or even a 740 or even 750 scorer...the 690 will get the preference over others...
at the end of the day...they want a well rounded candidate...not just the one who has proved himself in the world of "education" by getting a better GMAT...but in the world outside called "community"...so chill...
its upto you to decide whether to take GMAT again or work on getting a solid app...if you have time...i.e applying for next yr...u still can give it another shot...but as i said above (and i am sure many others would agree)...its ur decision and whatever makes u happy and satisfied...
hope it helps...good luck...