I am STRONGLY against watching that series for the following reasons:
1) I watched the Message once and since than everytime I think of Hamza(RA) this persons face comes to mind
http://en.wikipedia.org/wiki/Anthony_Quinn
so I don't want to soil the image I have of Umar Al-Khattab(RA) nor do I want a random dude, who could be unscrupulous in real life, pretending he is Umar(RA).
2) In Islams the ends don't justify the means, the means mean everything. For example We do decieve our kids into beleiving a burly bloke with a read had and reindeers will give presents if they are good kids in order to instill good morals in them.
Acting is a form of deception and thus inherently devoid of blessings. If their is no blessings than the means are wrong and a good outcome can't be hoped for from Allah Most High.
3) It is a doubtful matter and the Pious stay away from doubtful matters:
“On the authority of Abu Abdullah al-Nu’maan ibn Basheer (may Allah be pleased with them both) who said: I heard the Messenger of Allah (peace be upon him) say, ‘That which is lawful is clear, and that which is unlawful is clear, and between the two of them are doubtful [or ambiguous] matters about which not many people are knowledgeable. Thus, he who avoids these doubtful matters certainly clears himself in regard to his religion and honour. But he who falls into the doubtful matters falls into that which is unlawful, like a shepherd who pastures around a sanctuary, all but grazing therein. Verily every king has a sanctuary and Allah’s sanctuary is His prohibitions. In the body there is a morsel of flesh which, if it be sound, all of the body is sound and which, if it be diseased, all of the body is diseased. This part of the body is the heart.” (Recorded in Bukhari and Muslim)
4) Acting for the sake of education is Bida' and not done during our Prophets lifetime. If a Bida' occurs we need to see if the Ijma of the Ulema permit it and in this case I believe the Ijma is against it. If it was such a good idea there were means to perform before like they do in theatres now but it still wasn't performed.
5) It opens the door for more destructive events. Islamic Shariah is made such that prevention is better then cure. This series desensitizes Muslims such that they may find it acceptable to portray the Prophets(AS) which is not acceptable as it will soil their image. No ammount of performance will do justice in portraying what they are and what they did.
6) Allah Most High told us "IQRA"; read/recite. We will therefore always prefer this method of learning; by reading and reciting. We will encourage this and prefer this method as it aligns more with the Commands of Allah Most High.