While I'm all fine with character development, I also want Black heroic characters to be very useful and effective in a fight and/or have cool powers and/or special weapons. Frankly, I was hoping for all three of the lead characters to have Force powers (which might still turn out to be the case in the next 2 movies).
Here's the thing, while I liked Han (I liked his attitude/personality, which I found to be very funny), I always preferred Luke to Han because Luke had Force powers and a cool Light Saber. Based on what you have said, Finn is basically the Han Solo of this new trilogy, which I'm all fine with as long as he is useful in a fight and/or have a cool weapon or Force powers. Based on what happened to him in this movie, it might be possible that he might receive some bionics, which I would be fine with.
If the reasons why you like these characters hinge upon them having "cool powers and a cool lightsaber," then you're really selling the entire cast short. There is so much more to them than that. You're entitled to your opinion, of course, but that strikes me as an all too narrow and arbitrary criteria for picking favorites; you're destined to be disappointed if that's the only thing you'll accept.
As an aside, I think a big part of the reason we're seeing so much outcry and discontent over Phasma, Hux, Finn, and several others is that a lot of folks latched onto these characters and convinced themselves to fall in love with them. We see this a lot with the superhero movies, but the biggest difference is that in those cases, we at least have a point of reference with the comics and related media. We need to keep in mind that these are freshly conceived characters here; our preconceptions and expectations for them were never based on anything concrete or previously established.