in my opinion it is worth it too.
i have played it for about 20 hours now and i like it very much sofar.
i too think that fallen enchantress is a great game and that legendary heroes has improved it even more.
but you asked if it is much different from fallen enchantress and i don't think so.
it is still the same game, the same feeling, the same world, the same lore/fluff, just the mechanics are more refined (but i think that is a good thing, since i liked the old game/world/setting very much).
i like all the new mechanics, especially those random events, they let every session be more unique.
i tend to play archer heavy and when i watched some let's plays it seemed like archers got really weak, but that is not the case, they are as good as in the old game.
i like the skilltrees for the heroes and in some peoples opinion they are inbalanced (warrior and assasine are treated like they are weaker than the others) but in my opinion all is fine, i mostly play on expert world and hard enemies and if you "plan" on what you want to do with your heroes then an assasine/warrior can be as "strong" as a mage, they just work in other ways and i think people have to get a feel for that.
some people also think that the new system that you start closer to the enemy army on the battlefield is not an improvement. i had fears about that too in the beginning (esp. in some bossfights), because i like ranged units.
but sofar i had not one battle where i would say i felt the closer starting positions were a disadvantage for me, i am only 20 hours in the game though so i may not have enough expierience to say much about that.
they deleted weight/encumberance from the game, but they did it to a point that you do not feel the difference in the gameplay much, it just got smoother but has not lost complexity, since the stuff that had much weight in the original game now just makes your initiative lower, so they just deleted the "number" weight but the impact on your initiative that "heavy" items have is still close to what they had in the original game.
they deleted the armor and attack types (blunt/cutting/piercing) and gave every unit some skills instead, so the game lost some complexity but at the same time got some new. i like the skills and the complexity battles get from them, but i think losing the complexity from armor and attack types is still a loss, i would have loved it if they kept the old stuff and added the new too.
i think that sums it up quite well, if you want to see the changes for yourself i can recommend Das123's let's play, which you can find here: https://forums.elementalgame.com/444773/page/1/ he also has a quite wonderful voice 