I agree. I have played the game since November of 2015. Apart from the first 2 days of mods, tournaments are the single worst part of the game.
They're not about any of the things a "tournament" should be about. They're not about strategy or roster depth - where you finish has nothing to do with those two things. As you said, it has more to do with how many hours you can grind (6-8 for a top 25 finish - minimum) and which shard you are lucky (or unlucky) enough to end up on and whther or not you can play enough at the end of the tournament time.
And that's not even taking into account that as a way to introduce new characters, tournaments are a complete waste for a majority of players. Less than half of 1 percent get a 7* character (i.e. A "usable" hero in most aspects of the game) and only a very tiny group get any character at all. Since no tournament characters (or ships) are farmable, a large majority of the player base has a handful of useless shards for hours of effort and several hundred thousand ally points.
At first, I thought they could tweak the system to fix it. But there are simply too many drawbacks and flaws - it really needs a complete overhaul.