Is this game intended to be a modernized Baldurs Gate 2 style of game?
-> No. I can see where this questions comes from, but D:OS is a tactical, turn-based combat RPG. Whereas BG2 is a tactical real-time combat RPG. That's a huge difference. Still, if played BG2 as a tactical, turn-based oombat RPG (which you needed to do at the higher difficulty levels), then yes, D:OS is a modernized Baldur's Gate 2 style of game. Yet, when you like to play a fast paced real-time combat RPG, D:OS doesn't let you do that (whereas BG2 did).
Will this game follow the plot and lore of the previous Divinity games?
Yes, but it's a prequel, not a sequel to previous Divinity games. But the lore is true to the previous games.
I am contemplating if I should purchase or not. I don't want to play the game until it is finished but I would like to purchase it just to support Larian.
Go ahead and purchase the game then. I'm sure Larian will greatly appreciate your support and the extra money will go into development of the game.
If the game is not really an RPG but more just a tactical game like their last release.. I may have to pass then because that doesn't really interest me.
No, D:0S is first and foremost a RPG with an engaging story, character development with tactical turn-based combat. D:OS is NOT a strategy game! Not at all, it's an RPG with tactical turn-based combat. That's something completely different than a strategy game like Dragon Commander. D:OS is an RPG, rest assured!