As someone who's beaten the original 5 or 6 times, there are a lot of annoying spots and cheap bosses that I hope they fix up. The whole Sage Joch segment, for instance. I love the game, but the more I play it the clearer it is that its development was sideswiped by the CD add-on cancellation. Hopefully they take this opportunity to make this the game it always should have been. The combat system, music and art were all incredible, but the content held it back.
Not totally sold on those visuals... I'd rather have seen something like Muramasa: the Demon Blade with modern HD spritework. That'd probably be a lot tougher to do with an isometric perspective, though.