Well yes, we wanted out game to be memorable for having a respectable amount of dragons. Who doesn't love dragons? As mentioned multiple times, we managed to achieve a pretty good balance between our mons (there are somethings which would be horridly broken out of context, by Graterras offers specific hard counters to them), meaning no type has a distinct advantage over any other... And that being the case, we figured it would be interesting for people to have access to options for monos that usually aren't viable in other games. And from an in-universe point of view, Fairy is the type so rare it is considered almost mythological (yes, there are many representatives available for that one too, but the fact is, there's only one per area, and they are all Elftik-rare, so good luck with that ), so yeah, Dragon, while still a rare type, is not as strictly late game as it used to be. As for the 3 non-dragons that evolve into dragons, all I can say is that only one of them has been announced so far.
To expand more on what I said earlier:
- Ground, as mentioned, has the problem of offering virtually no options until you get to a specific area.
- Normal offers lots of variety early on and can get you past the first two gyms, but loses steam afterwards.
- Bug offers enough variety to deal with Mary (Sinisect and Chromalyd are popular choices to deal with her, after all), and has some interesting new members in Ep 2 areas, making it an overall solid choice.
- Fairy forces you to face Mary with only 2 mons, and between her and the second gyms, you can only find two more mons... Both of which are weak to the second gym's STAB. It becomes a very solid mono afterwards, but the early gyms can prove to be a nightmare...
- Grass is probably the best choice, on the account of including a solid starter (whose offensive options have been patched up in Ep 2), a hard hitter in Pikrieg, and resident crutch character Mouroot. You get another solid member before the second gym and yet another one immediately afterwards, and while Mouroot looses steam at the beginning of Ep 3, that's when one or two more good mons become available. Grass is indeed a solid, well balanced choice for a mono.
- Dragon forces you to solo Mary with Lifoam, and it also has the issue that, of the Pokemon available before the second gym, two are destined to evolve into dragons, but as of Ep 2 you have no way of knowing which ones. Once you unlock the final areas of Ep 2, and get your hands on Bloanna and on the secret soon-to-be dragon, your team suddenly goes from mediocre to stellar, but the problem is getting there. Really difficult choice early on.
- Fire forces you to solo BOTH Mary AND the second gym with Roobber, which... Isn't really doable. Afterwards, you get some VERY strong guys, and even more in Ep 3, but still, the issue here is getting past the first two gyms.
- Dark has you fight Mary with only two Pokemon (Ebounny and Sinisect, which admittedly isn't that bad), and while you can catch a third one before the second gym, it is weak to the gym's STAB. The fourth Dark-type is caught at the end of the episode and is a VERY unique one (come to think of it, we announced it a long time ago...), and Ep 3 offers a couple more options to round out your team, making it a very well balanced choice... But once again, the problem is getting past the first two gyms.
- Fighting gives you two mons to fight Mary with, a third one immediately after her (which is actually pretty good against the second gym), and a fourth one at the end of the episode. With more options coming your way in Ep 3, this isn't a bad choice overall... But good luck beating Mary lol
- Water forces you to solo Mary with Lifoam. Which is a pity, because immediately after her you start getting some great diversity, making it one of the best monos in the game. If only you could obtain a fishing rod in Ep 1 areas
- Steel has no representatives before Mary, and only one between her and the second gym, so yeah, it isn't really viable. It only gets a mention because its 3 representatives (Kutlass, Bloanna, and a third one you still haven't seen) are all pretty strong.
- Poison has a very strong representative in Oppossite, and two more become available when you get to Eskatia. As things stand it is not a very balanced mono, specially considering that your main STAB would be scarcely effective against the first FOUR gyms, but you do get some long-term potential.
- Electric gives you Pikrieg, which is actually pretty strong against more or less every enemy in Ep 2. Problem is, your second representative is rare and kinda weak early on, and as of Ep 2 you don't even know who your third representative is...