If you were baptized having ANY discussion would be disasterous for you with nothing to gain.
Since you are NOT baptized, you have nothing to lose, but you must convey some sincerity or they will just "write you off", dust off their feet (cast no peals before swine).
Here are a couple common issues to consider -- (SORRY SO LONG):
The 607 date -- This is a big issue for many. Why so? A simple summary is that NO ONE in history agrees with 607 BC being the date that Jerusalem was destroyed. There is virtually nothing published to argue against 607 because no one believes that, except JWs. And there are so few JWs that they are inconsequential in the academic world. So why are JWs so adamant about 607? Because it leads them to to 1914 (via the 7 times prophecy) as being the year of Christ's enthronment and subsequently the WTS being chosen as "special" and appointed by Christ as the F&DS in 1919.
However, you will get nowhere with this on the hardline JW Elders. They will say the Bible indicates 70 years from 537 BC so count back and you arrive at 607 BC. Who do you trust? The Bible or "worldly" history? And they will pull out the Oct/Nov 2010 (?) issue of the WT where the WT makes a lengthy, confusing, convoluted attempt to support 607 BC that the average JW would find brilliant and baffling and never be able to prove or refute.
The BLOOD ISSUE could be a bit more simple to argue. The keystone scripture is Acts 15:29 where it says not to be burdened with unnecessary things, but only these 3 things: ". . . to abstain from BLOOD, from things sacrificed to idols, and from fornication." The fact that is says "abstain" here is applied to mean more than just not EATING blood. Interesting is that later Paul said it was OK to eat meat sacrificed from idols (so long as others were not offended by you doing so). 1 Cor. 10:25-29 speaks of eating something said to have been sacrificed to idols. Paul does not condemn the action, but only the possibility of stumbling some other person from doing so. THUS, was the command in Acts really binding on all Christians for ever, even today?
Old Testament example: 1 Samuel 21:6 where David & his men are "starving" (not really life or death starving -- just hungry) and they eat the Holy Showbread that is to be eaten ONLY by the Priests (under penalty of death to anyone else doing so). Is there any difference from this example, and someone today taking a blood transfusion (blood being said to be Holy and reserved for Jehovah) if a person is REALLY dying if they refuse to do so?
Clarke's Commentary on the Bible: So the priest gave him hallowed bread - To this history our Lord alludes, Mark 2:25, in order to show that in cases of absolute necessity a breach of the ritual law was no sin. It was lawful for the priests only to eat the shew-bread; but David and his companions were starving, no other bread could be had at the time, and therefore he and his companions ate of it without sin.
Further, Deut. 18:21 forbids the Israelites from eating unbled meat containing the blood, yet they could SELL IT to a "foreigner". IF eating the blood was condemned by God, was it only condemned for an Israelite to do so? NOT for a man of the nations? Is this really Jehovah's universal law on blood? Guess not!
Eating vs. Transfusion: They'll use the Reasoning book's blurb on a doctor ordering a patient to abstain from alcohol, and asking then if it is permissible for the patient to "transfuse" alcohol intraveneously? Would this be ignoring doctor's advice? This is NOT an "apples to apples" comparison. Rebuttal: Patient is rushed to hospital with hemmoraging blood loss. Doctors say he requires more blood, and has patient DRINK two units of blood. Would patient survive? NO! because eating is NOT same as transfusion. The patient does not FEED on the blood put in their veins. Transfusing blood into one's veins is the natural, "God-designed" rightful use of blood and is NOT the same as "eating" blood.
And it gets even more muddled with the new allowance for "blood fractions" which JWs can allow under the "new rules". Why did the Holy Spirit direct that (in 1940s) ALL blood products be avoided, but in 2000s is OK for SOME blood products? What about all the people that died if they'd have known that is was OK with Holy Spirit/God to accept some of the life-saving blood products allowed today? (Justice? Righteousness?)
Further, a JW cannot have their blood stored and used later (for example) during their surgery as it is to be "poured out to the ground like water" (Deut 11:16, 20-24) -- NOT saved for future use. [There are rumors that this rules was going to be rescinded, and new blood cards were even printed with the new information, but the decision was reversed at the last minute and orders given to destroy the new blood cards.] Again, how much or how little is OK to be stored? For how long? JWs commonly allow "blood tests" where their blood is drawn and "stored" in tubes/cylinders for medical testing. Is it OK for just a little blood to be stored? How much is "a little"? 1 ounce? 1 cup? 1 pint? And what future use is acceptable? Examine under microscope? Mix with chemicals? Spun in centrifuge? Re-transfused into your own body? What scripture says so? They say it's up to one's own conscience. But what if you decide to have 1 pint stored for transfusion during your surgery? Is that still up to your conscience?
If it's OK to "store" a little bit of blood despite the command that the blood is to be poured out, how about a little bit of fornication? Is that OK too? (I think a BJ would be just a "little" fornication, but that's JMHO.)
Elders/MS & others appointed by Holy Spirit -- I'll guarantee you that those Elders know of Elders that should never have been appointed as Elders. In our area we had men appointed that were involved in ongoing adultery for years, and even homosexuals and pedophiles who were appointed. How did the Holy Spirit NOT know of the sins of these men and allow them to be appointed to serve in God's Congregation?
If you don't know of one locally, consider this one of many: Manuel Cano, a Bethelite Elder dispatched repeatedly to events all over the country representing WTS. He was soliciting young boys while on his travels for WTS. Did the Holy Spirit not know what he was doing during his travels? Yet evidently Holy Spirit allowed him to continue to be "used" by Jehovah's Spirit Directed Organization:
Is the Holy Spirit really making these kinds of errors in choosing men to represent God's Congregation? Or, is the Holy Spirit not really involved at all? Which makes more sense to you? We know they admit that "imperfect men" make mistakes. But are these the mistakes of "imperfect men"? Or, is the Holy Spirit involved in such errors too? If it's just the "imperfect men", then we must ask: Is the Holy Spirit really having any role in appointing Elders in the Cong? or, even members of the Governing Body? At what level of WT politics is the Holy Spirit really involved in decisions? Any? or, None?