The 4 burner hob is fine, we did have 5 rings on our old cooker - however we never used more than 3 hobs at any one time. We tend to use an electric steamer for veg mostly so no need for saucepans for each veg.
Didn't you have
seven? I counted a 3/4 split - hence me asking why you downsized, when most people upsize.
If you don't use the hob that much, for whatever reason, then fair enough.
As for the dim look, we are still looking at under mounted down lights and they will make it feel more airy etc.
I think you are going to need it, but I wonder if you might have a problem with your dark, shiny worktops... I am so used to lighter colours that I can't quite fathom how it will all work!
That being said, with your wife being a cake decorator, she's going to need some decent lighting to do that - at the moment she'll be standing with her back to your batton, casting a shadow. Will she get enough from under-cabinet lighting?
We do have less worktop space than before - this is right, however the space previously was wasted and not used fully. We have plenty of space to do what we want to do still. We have 6.5m of worktop lenght in total still, but better storage now.
Will overhanging storage over the large majority of your worktops make life tricky for your wife? The only open space is right next to the window, but standing there is going to be a little restricted with the positioning of the appliances?
I'm not a fan of working under cabinets, but sometimes I guess you have to. That's why I've pulled my units out past 650mm to give me as much front-to-back space as possible.
And speaking of storage, did you consider a corner unit to the left of the window? You would have eked out a little more space that way. And was it a conscious decision to leave a gap between the wall units and your hood or was that through available sizes of the units?