[How do you think if the game Fire Emblem : Blazing Sword remade into a better game and was also made into an anime?]

Why not make it like FE4? If they do remake FE7 they should pair it with FE6 and if certain characters reach max support they have their children that are from FE6 but it will be a whole different story arc (like in FE4). Characters will inherit certain skills and stats.

[Karel or Harken?]

While I do prefer Karel, Harken outclasses on hard mode which does put him at a huge advantage. He also comes with a brave sword which is a subjectively better weapon than Wo dao. Karel is by no means a bad unit (except for that disgusting defence growth). I personally prefer Karel because I think he is a better character and I like the Swordmaster class better.