This is a really personal decision about how things work and look.

The doors themselves are going to be around 21" wide. Forgive me for not bothering with the fractions but I don't think it matters too much. 15" deep cabinet + 21" door equals the door extending about 10 inches further into the room than the counter top. So there is a potential for getting face-hit too.

Me, I wouldn't do the glass doors cause I share your concern for needing stuff in the cabinet to look pretty (better things to do than worry about how 86" of upper guts appear). I'd have some concern for cleaning the glass - particularly if there are grids. Also concern of the glass doors banging into the sides of the oven or hood resulting in broken glass or beaten looking cabinets. I know there are some door stop devices but again, we're just not that careful of stuff but you might be fine.

You might think about asking after sliders and/or decorative glass that somewhat obscures the interior view. Think about whether it would work better as 27/30/33" uppers and a gap before the hood, altho doors might stick out over the counters by 4-5". Another thought would be paired 21" cabinets instead with the resulting doors that are 10-11" wide. The door would still be just at the edge of the counter or just a little bit longer.

I like glass front cabinets, but am limited on what i can put in them. How narrow is the smallest I can go for a glass front cabinet and still have it be functional and attractive? I have one glass front cabinet in my current house where the door is 16 inches wide. It is a decorative cabinet. I don't want any cabinets that are just decorative in this next house. The kitchen is smaller than my current one and I need all the space to be functional. I am kind of thinking I should shrink the hood by 4-6 inches and have two smaller glass doors (a 27 or 30 inch cabinet) and one single small full cabinet door (14?). I have two small full cabinet doors in my current kitchen (12 inch door) and they are functional.

What kind of hood are you planning? I like it when there is a few inches between hood and cabinets for breathing room. If you did that, those uppers would be several inches narrower and might be a better width for your needs. There are some great types of glass that obscure the contents so you wouldn't need to worry about making the interior shelves look pretty. Blendheim Glass has many to choose from.

I am planning a hood similar to the one I have now in this pic. So, I wouldn't want space between. I have pretty much decided to break the space into three: one small wood cabinet and a two door glass cabinet. I appreciate the advice from all. Here is my current hood--similar to what we will do this time around. Also, you can see the glass cabinets I currently have. I have another set on the other side of the big sink, which you can't see. They work well for us. We keep the pretty plates and glasses in here. They measure around 30 (14ish for each door).

Agree the center stile is something to ask the cabinet company about. We had one 39" and one 42" wide upper in our old kitchen with traditional framed cabinets. Both had glass doors but both also had a center stile which no matter how you organize always seems to be in the way. Other than that we actually liked the width and did not find the doors to be "too big". We only store dishes and glasses/stemware in these uppers so they look fine behind glass. Our other uppers have ugly stuff behind them like mismatched souvenir coffee cups, K-cups, paper plates, and assorted store bought bottles of spices so those go behind solid doors.

Any way you look at it there's a lot of personal preference in this decision I think.

Below are pictures of our 15" deep, 40 inch wide, inset doors, cabinet boxes. Our counters are 27" deep, which helps with the wide doors. The stiles are 2". The doors are just a bit over 18" wide. Works great for us. I wouldn't want 3 doors, nor would I want to get much wider. Funky has a good idea to deal with the boxes right and left of the hood. You would lose that space making 3 doors anyway. Also, I see you have a corner cabinet. Have you considered squaring it off and making it an easy reach cabinet? Also, in my world, I would flip the freezer and frig.

Our door stiles and rails are 3.5 inches and I don't think glass would be too much, but we decided not to because of the shelf we put in next to the cabinet. If we went with traditional 2" panels, it might be too much glass. I don't know.

ETA - I wouldn't want the center style for function reasons as Stan mentioned above.