No, they are not. Being able to reposition is isn't relevant for a game system that much doesn't care about location.
so flanking isn't a thing then? it's an optional rule but it's still a rule, and you can still let an ally move without taking an opportunity attack, or attack ranges, positioning can matter for those.
just because 5e doesn't do it to your personal satisfaction doesn't mean it doesn't have it.
Additionally, tactics are knowing what moves to use and when is the best time to use them. In 5e, those are just simply the actions that characters have whether it's Help, Dodge or Disengage, or using movement to find Cover, or your attack to Shove. They are available to all characters, so how do you really represent one character being better at all of those things, and able to make others better at those things without also unbalancing the game? In the end, tactics are about putting your side in an advantageous position - how do we do that? Give people advantage. Give others disadvantage.
Really, there's a lot of classes and subclasses that are some form of tactician already whether it's the Battlemaster, the Mastermind, or pretty much the entire Bard class.