My initial impression - I don't like the changes but it's not game breaking and I think everything will be fine in the long run; except for Rohan, they are just as bad as before.
What I don't like:
1. The Warbands rule. You have to have a hero for every twelve warriors. This forces smaller armies. The hordes are pretty much dead. There's nothing wrong with hordes. It was a viable army build. In return for more warriors you had fewer heroes. Most factions don't have cheap heroes meaning a bunch of troops are going to have to be dropped to fit in the extra heroes. This rule just takes away options from the player. I'm not sure what problem GW was trying to fix with this.
2. Rohan. WTF GW? The Riders of Rohan are the only models in the entire game which are forced to pay for an option that they are not allowed to use. You still have to buy a bow for every single rider even though only a third of them can use them. The points saved on that one thing could have made a big difference for this army.
3. Gondor. Faramir, Captain of Ithilien is gone. He does not exist as an option anymore. This seemed a little harsh. You paid a lot for his abilities. He wasn't undercosted. He's just gone. My Gondor army will have to be completely re-worked.
4. No restrictions by age. I could now, legally, have an army with Aragorn and Gil-Galad. Tournament organizers can make rules on this but it would have taken virtually no effort on GW's part to make sure this didn't happen. Instead, as usual, they fell back on, "It's not nice to play this way so please don't".
5. Far Harad. Now they are just another troop type in Harad. They used to be unique and interesting beat sticks. They were expensive but they were hard hitting shock troops. Now. Not so much. They cut the cost by almost 50% but they cut the awesomeness by 100%. These guys may make it into my army but they were the main reason I started collecting Harad and now they are just Blah.
What I do like:
1. The deployment rules in the scenarios. The random nature of deployment, coupled with taking turns to place your warbands adds another bit of tactics to the game. You have to build your warbands in such a way that they can survive without support. You get a chance to react to your opponent's deployment, and they to yours. I like this aspect of the warbands.
2. Rohan Outriders. These guys are much closer to what they should have been all along. I like that they are just a troop type. I like their special rule. I like that they are a viable alternative to a regular rider but not a no-brainer choice. I really like that the Gamling+Banner of Rohan+all Outrider army is D. E. D. Dead. That was an abomination.
3. Troop options. I like that some heroes unlock certain troop types.
That already existed but there is a bit more of it. I also like that
there are some normal troops who can be upgraded to have extra skills.
Anything that gives more options to the player is a good thing.
4. Serpent Sting Rule. This is a nice bonus for Harad. If all models in a warband are from a select list then you can have 50% bows instead of 33%. I like this because it makes Harad more viable but also because GW sells Haradrim in a set that is half spears and half bows. They don't give a handweapon option. With the 33% rule you were paying for models that you were unlikely to be able to use. It's nice to see some consideration for the buyer.
Overall I can live with the changes, which is good since I don't have a choice. I'm not happy about a lot more than I am happy with. I'll have to see if I can make Harad interesting enough to keep playing it. This was going to be my tournament army for the year so I need to figure it out soon. My Gondor will need a complete reworking. My Rohan will not change too much, though I will need to paint up some more models that I already have and perhaps buy a couple more Outriders. My Isengard may get some additional models but is not affected very much by the changes.
Overall, I'm happy to see the system getting some love. I expect that there will be more releases this year, which will also be a nice change of pace.