As you may know, 1.6 added two new monsters to the game for players who have the DLC. (Note that the DLC is required to encounter these monsters.) The question comes, of course, how to get them, and here's how:
* At some point, you will get a mission that mentions the new monster type. Clearing it will unlock a hunt, on one of the spots that normally has a large battle.
* The hunt will have you fighting a tier 3 boss of that type, as well as a tier 1 normal enemy. I recommend taking Bzaro and somebody with the Wrangler skillset; this will get you 3 essences from that monster type if you tame the normal enemy. (Note that there's other enemies in the hunt, and Extra and Elite enemies will appear if the difficulty allows them.)
* If you want to catch more of the monster, or you want to get more essences, you can do a large patrol of the map; one of the enemies on the map will be replaced with a tier 2 monster of the new type. This happens only if you've beaten the hunt, but the new monster will always be present. (Note that you do need to beat the large battle here before you can patrol.)

If you catch the monster in the hunt, and you use Bzaro both times, it is possible to get the class for Bzaro doing only 1 large patrol.

(Note that I haven't actually done this myself; I obtained the information about the enemy showing up in a large patrol through data mining.)

I know this is a really late response, but thank you for passing on the info. I don't own the game yet, but I'm considering it during this sale (fantastic price also) and this bit of info intrigues me enough to seriously consider getting it today or tomorrow.

I held of for a long while because the game maps always seemed so small, so I thought the world was also small and not much to see. But the reviews and ratings are high (time to beat is also high), so maybe I thought maybe I shouldn't just judge it from just the trailers and images alone.

Anyway, this info does sound like there may be plenty of secrets in this game and for my in RPGs, it's always nice to explore or discover new ways to obtain things. So I hope this isn't the only secret in the game lol.

But my only concern (as has been for many RPGs), is one fact: can the player discover all this during the natural course of the game? What I mean is, if these secrets are too obscure, then even players who put in serious effort (while having fun ofc), may not discover it no matter what. I don't even know how many of these people discover these hidden gems in the first place.
.

From what I remember, it shouldn't be too hard to discover this on your own.
* Bzaro just joins your party through a mandatory story event. I don't remember if the game explains how you get classes for him, but it works the same for all of his classes.
* For monster recruitment, just follow the missions that the DLC adds. You'll eventually get one that unlocks the class that can catch monsters, and monster catching is significantly easier than in other similar games I've played in the past. (There's also some missions that give you monsters.)
* I'm pretty sure these new monsters are meant for the player to find normally, seeing as how they were the primary focus of the update. (Also, as a carrot to incentivize people to purchase the DLC.)

That's good to hear and thanks for the reply. It sounds like I'll be getting the game, seems worth it from everything I'm hearing. I still had to ask around just in case, cause even after the best reviews, some games are just not mean for you and you won't know until after you try it. Too many started and not many finished lol and many highly rated.

Oh yeah, I almost forgot to ask, but how is the replay value for this game? It's not a huge thing since I still have a huge backlog of games, but nice to know ahead of time since it'll be a little while before I can try it out even after buying it.
.

Well:
* There's plenty of different classes to choose from, each with their own abilities and characteristics.
* You can equip each character with a secondary skillset from another class. This leads to all sorts of interesting combinations to try.
* The DLC adds monster recruitment, and also monster variants, giving you more possible builds to try.
* And, of course, there's the difficulty settings I mentioned, so you can make the game easier or harder as desired, and in different ways.

So, plenty of build options, meaning plenty of replay value (just try out different builds than you did last time!).

I decided I'm gonna get the game tomorrow. A lot of the details you mentioned so far has got me too curious about the game now. :)
.
Edit:
And...bought! :)
.