I am in the middle of the third island and I'm neither happy with my team right now, nor have I even landed on six yet.
Current team:
Alolan Marowak Lvl 36
Lycanroc Lvl 40
Decidueye Lvl 37
Toucannon Lvl 36
Espeon Lvl 36
I want to keep Marowak, Lycanroc and Toucannon, but I would have no problem getting rid of Decidueye & Espeon. The former falls in the long line of final starter Pokemon evolutions that I don't like (The original three are basically the exception & even then I only really love Blastoise and Bisaflor). and Espeon is a glass canon that goes down like nothing, which is not really fun.
Still waiting for Ice-Vulpix to appear, will straight wander onto my team. But eh...not particularily happy right now. Worse, that all my other favourites I want to consider fall all into the same 3, 4 types or are also Kanto-mons. Growlith, Snorlax, Haunter, Herdier, Pangoro, Komala, Golem.
But... I have to say... that makes it almost more worthwhile to keep playing. In the beginning I was almost worry I locked myself in to fast without much room to change. Now it is more a journey of figuring out which Pokemon are perfect for me. It does help that I don't know the Pokedex.
Man I love this game... (this post sure did a 180 haha)