The argument of "it gets less tactical if RNG is too strong" is pretty much void of meaning, there is no correlation there.
Divinity 2 currently has no RNG on crowd control and there is absolutely no tactic required on the combat part of it. There are too many ways to reposition and whoever is out of armor will be stuck on permanent CC.
In a game with a strong RNG luck is as important as tactical decisions, because your perfect plan can be ruined by a single dice roll.
It's called bad luck. Sometimes the best made plans go wrong.
Also, if this happens to you alot, maybe, just maybe, your plans aren't as good as you think they are. In games with die rolls and/or percentages there are usually ways to improve your odds through careful planning. If you're ignoring that aspect of the planning stage then yes you'll often find yourself on the wrong side of the die roll. Calling die rolls RNG, isn't really true either, as your bonuses through stats, abilities, talents, and environment should improve or hurt your odds given the unique circumstances of the encounter, which takes the randomness out of the equation. A random die roll wouldn't take anything into account, it would just be a set chance that's completely unaltered. That would be random. A die roll that takes your bonuses into account is not random.
Sometimes stuff happens, and as humans we tend to focus on the times stuff goes badly than when things go well, but I find that my character is DOS 1 makes his saving throws quite often. If I ignored it or didn't realize how often I make my saving throws I'd think it was random too, but that's not the case.
Removing chance from the equation makes the game stale and repetitive. It's boring to have things go as expected every time just because you met a certain criteria. It removes those heroic moments where you overcome the odds too.