Just finished Conquest, clocked in at 40 hours. This is easily the best English Fire Emblem in terms of gameplay. The new weapon triangle feels balanced, especially now that bows aren't worthless. Rebalancing the weapon materials was another great decision, I like how the lowest tier is your safest bet, and as you get more proficient the option to take more risky options (weapons) becomes available. There was a great amount of objectives and creative use of the mechanics, shout out to the level with the hidden boss and the level that changes flyer and land unit speeds. Just rating it on this part of the game it is a 9.5 easy.
The story now... Whoo boy did they screw it up here. The characters, with a couple of notable exceptions like Xander, feel poorly written. The supports are at least a little better then the main campaign. It went from a cool premise, to cool possibilities, to the most stupid thing I've ever seen. The whole last arc revolves around the possibility that something may work if they do this thing. Honestly one of the most obtuse plot threads I've seen in a game. Rating it with the story added in, it would be an 8.5.
For anyone on the edge reading this thread, it is well worth it if you go in knowing the story is garbage.