Focussing on long haul business

Lack of storage space for in flight items - iPad, headphones etc. Qantas skybeds being a worst example and their latest A330 suites along with Qatar 787 suites being an example of this done right (water bottle and headphone storage in the armrest for Qatar a particular design triumph)

Headphone plug that is hard to find, especially in the dark. I think a lot of designers have woken up to this and are placing it in more obvious and easier to plug in spots

Tables that require you to sit up and have the leg rest down. Thats you Cathay and ruins what is otherwise one of the great seats. Take a bow Qatar 787, the best designed table I've used

Trapped window seat passengers. OK, this is starting to be solved by everyone moving towards all aisle access seating but why is it so difficult to design in a step and a handle into seats which have a window and aisle seat. This would make things a hell of a lot easier for the window passenger to get out when the aisle passenger is sleeping. No excuse for this oversight imo

Seats where the legrest isn't really independent from the backrest. I generally like my legs up and but I'll have the backrest at a different angle and seats which make this difficult really annoy me

Leather seats. Leather doesn't breath and has no place on an aircraft. Pleather even less so.