What makes you think that a pro bono criminal attorney who will be paid nothing, is going to devote more time to your case than an appointed attorney, who although, not being paid as much as private counsel would be, is at least getting paid something, albeit by the state. And if you are already considering a malpractice case against your current counsel, do you really think pro bono attorneys will be lining up to take this matter on.....Oh, that's right...you said it was an open and shut case !
You already have a court appointed lawyer at county expense. It is unlikely that a different lawyer would accept your case for free simply because you ask. People accused of crimes who can not afford an attorney are assigned court appointed counsel, but court appointed counsel and pro bono lawyers are not for people who choose not to hire a lawyer. It is also not possible for the lawyers in this forum to point you in any meaningful direction since you have not explained your situation and circumstances. It is very unusual for a criminal case to go on for 5 years as you mention. Without discussing any potentially incriminating facts or evidence, consider providing a basic who, what, when, where, how and why of your case so others here can try to help. Good luck.