In my opinion / experience, often the effectiveness of an admissions consultant can be determined by the chemistry between the applicant and the consultant. you could have a perfectly good consultant, but if his/her style doesn't mesh well with yours, then it's very difficult to be effective. it might be that this chemistry is "off" with whomever you've been working with. if that's how you feel, i'd move on. you've already obtained the insights and advice from this person, and if you were not admitted the first time with him/her, there's no reason to think it'll happen this next time, unless you've really added a lot of new content to your application (which is perfectly reasonable as well; i've seen this happen).
in finding your next consultant, my advice is (and this is very difficult) to focus on 2 areas: (1) what is that person's knowledge on the schools you're most interested in. the programs are very different and look for different qualities. make sure your consultant has some familiarity with your SPECIFIC program. (2) was that person actually on an adcom at an MBA program, or is s/he more of an editor? my belief is that it's important to have actually served on an adcom. you read thousands of essays at once and develop a sense on "where the bar is." there are great consultants who have been trained into the job, but IMO, there's nothing that compares to the actual experience of sitting on an adcom and making a judgment on hundreds of candidates.
hope that's helpful
Former Kellogg adcom member, offering a new approach to MBA Admissions Consulting.