Honestly if you don't have the base game, you're better off getting the Collection which is on sale for $40 right now. You get everything ever released up to Way of Life, which will pad out your game nicely. That would be the ideal starter pack, and as you learn the game you can add in Way of Life, Horse Lords, and Conclave during another sale (and CK2 goes on sale frequently). The only reasons I wouldn't do the Collection is if I was afraid I may not enjoy the game, if I was trying to penny pinch, or if I didn't have the time investment of around ~150hrs to learn the game.
And on a side note, if you ever see a bad review for a DLC it's more than likely that they're actually complaining about a free patch feature. Conclave got much of its hate from the infamy and coalition mechanic as an example, which ticked off a lot of "map painters". If you yourself ever find that a patch feature is problematic, you can always roll back to a previous patch using Steam Betas. Several older patches are kept for convenience in fact, going all the way back to 1.11.