The heroes are tuned down compared to 4th, certainly, the lack of customisation and obscenely powerful Magic Items makes sure of that, but they're definitely strong units that can multiply the effects of infantry.
Making sure you have the right ones at the right times is key to things going well for you.
The game as a lot to it that people are missing by focusing on what they see as negatives, yes there is no point system and that means it could be abused, but WFB had a point system that could be abused, people are going to be bad players to each other sometimes.
This way, when someone is a bad player, they can't pretend they're not because "technically the rules say I can do this" it brings the social contract that was always supposed to be there right to the front of things and makes it the most important part of having a fun game.
The focus was never supposed to be who can beat their opponent, that's never been part of the game, the aim is for the players to have fun, your objective is to win and your method should be to win in a way that doesn't invalidate the aim.
It seems a lot of WFB players lost sight of that aim, as people were trying to win without caring how terrible and boring it made the game for their opponent, which put people off playing it once they encountered that. It was a good game but in the hands of bad players quickly became a chore. A bad match up of 40k is one thing but a bad match up in WFB was soul destroying, mainly because it too so bloody long.