After being defeated with my mojadrain deck, I'm now making a more popular DrainTown deck (Skill Drain+GearTown).
However, I have seen Chiron in threes in every deck like this. Why? Are there any other BWarriors that can compete for that position?
Warwolfs maybe?

Chiron is mostly there for m/t removal and you can ditch extra/unneeded Magic Cards to activate its effect. Only good when Skill Drain isn't out anyway, where its 1800 A. It's not because of it being Beast-Warrior really. And not a whole lot of decent Beast-Warriors (splashable anyway) as it is, much less ones that'd benefit in that Decktype.

My main tactics in that deck is cycling Field Spells to bring out Ancient Gear Gadrilton Dragon and getting Beast Machine King with its special Summon ability, either as an ATK wall or as a great offensive monster whenever Skill Drain is out. Being very easy to summon, I can attack without hindrance with it.

Well, that's pretty much the obvious tactic given the Deck title. Though, as said, I rarely like Decks that focus so much on 1-3 cards so adamantly. Otherwise, if they get disrupted, then you pretty much lose a good bit of flow in the Deck.