You can check blacksmith upgrades & chemistry simply by clicking on the relevant unit types, so seems a bit unnecessary to add that and take up more space in the overlay.
The current situation means a caster has to click on the unit and parse that information and retain it in their brain. If we are talking about the viewer experience it's even worse... they might start watching the match at any point in time and it's hard for them to know that information. I liken this to Football / Soccer which started showing a team had a man sent off by putting a red card icon above a team's name near the scoreline. Playing with 10 men is a huge difference in the sport and if you didn't know it you might wonder why a team who are usually so good in possesion are never on the ball. To be fair though, they only show red cards and not the tally of total indiviudal yellow cards, so I do appreciate your point - a line has to be drawn at some point over what is and ins't shown.
I think for all blacksmith upgrades you would be right in that having ALL of that information on screen would be OTT. But it could be in a seperate tab that the caster can go to, to get an overview of the upgrades each players at any one time. "Damn Lierry just won that engagement despite having no Fletching or Scale Mail Armour!" is a lot more exciting than having a caster asking his co-caster "hey did Lieryy get Fletching yet? I can't remember." I can personally remember multiple matches in multiple tournaments where casters lost track of things... and I am not blaming them because it's hard to keep track of!