Okay, I'll bite - here are my answers for this form...
Favorite Actor: Gurmeet Choudhary (Rama)
The actor who is doing best justice to his/her role: Tough to tell, but I'd go with Debina. Reason for this - watching Dipika 20 years ago was painful, particularly due to her very weepy character, and her subservient attitude towards Rama. In this serial, Debina lends Sita both sorrow and outrage, and some places, such as Sita slapping her guards, or threatening Surpanakha, were amusing to watch, even if a departure from the script. In other words, Debina portrays Sita's pativrata aspect well, while lending her a fury born of a pride that would be expected in a kshatrani such as her.
Rate this Ramayana from 1 to 10 (10 being the highest): 7 (I share your reasons - it does deviate from the script quite a bit. For starters, I don't like Ramayans being based on Tulsidas, who distorted a lot of things, but even beyond that, it needlessly defames characters who were actually heroic, such as Vali: other than imprisoning Roma, he didn't molest others' wives, as depicted in the Mayavi episode - that challenge came because Mayavi and Dundoobi were brothers or son/father. Similarly, Bharat was never wounded in battle with Sita's other suitors).
The best aspect of this Ramayana: Unlike the previous serial which would prolong things artificially e.g. Angad walking to Ravan's palace, this one does it by filling in background stories, such as the episodes about Hanuman's birth, Vali's battle with Ravan, etc. Most of the stories about Ravan and Vali are actually covered in the Uttar Ramayan (I'm talking Valmiki here), but here, the stories about them, such as Ravan's war with Kubera and the conquest of Lanka, are beautifully inserted during otherwise boring episodes such as Sunderkand.
Something you found irritating about this Ramayana: The unflattering light in which some of the characters were depicted, such as Vali, Bharat. Also, some of the deviations, such as Ahiravan and Mahiravan happening at the beginning of the war, as opposed to the end. Not all the deviations were irritating - I liked the one where Sumitra slaps Manthara and condemns Kaikeyi for disgracing the throne of Ayodhya.
Top five favorite songs: So far, just 2 - the song played when Bharat and his retinue were going to the forest to fetch back Rama, and when Rama, Lakshman and Sita met the newly widowed Rajmatas.
What does this Ramayana have that the one 20 years back didn't?: A lot more detail and background stories, as mentioned above. Far better sets, and most noticeably, the special effects of the weapons were awesome, particularly in contrast to the 3rd rate 2D effects 20 years ago. Only complaint there - a lot of the Rakshashas are shown as disappearing when they were killed, but such delicate handling was needless. They seemed to improve that in the killing of Ahi & Mahi, so lets hope we won't see that in the yuddhakand. Another thing I liked during the Ayodhyakand was showing the other wives, such as Mandavi & Srutakirti during their husbands' visits to Kekaya-desh, and again when Bharat and Shatrughan were getting the news of their father's demise from Kaikeyi and Sumitra.
What does the Ramayana 20 years back have that this one didn't?: I agree with Durga here again - this serial goes too fast at places, like Hanuman's meeting with Sita, and elongates too much at other less significant ones, like Ahi & Mahi taking 3 weeks. The previous serial did some things a lot better - like when Bharat approached Kaushalya after storming out on Kaikeyi, his conversation with her there was heart-rending and touching, whereas here, it was just the third segment and Kaushalya almost reading his mind.
Finally, which Kanda of this Ramayana did you like the best and why?: For this serial, Kishkinda kand - although I don't like the way Vali was vilified (e.g. molesting Mayavi's wife, which didn't happen), I liked his conversations with Tara, demonstrations of valor that were shown by him, the extra coverage of Roma. Oh, and in Sunderkand, I liked how Hanuman's story was shown, and how Sita's defiance against her captors were shown. I do think however, that depending on how it is shown and how many warriors they show getting killed (I hope lots), yuddhya-kand might end up as my favorite, or at least should.