TOTM, you make some excellent points. It is a difficult balance, but MAN can't afford to neglect the more prestigious long haul carriers and their passengers in terms of the airport experience, especially as it is rightly focused on winning more pax from the wider region in its role as an International Gateway, passengers who might otherwise use LHR.
Just a personal view but having checked-in in a nice airy, spacious environment, I wouldn't want to find myself airside in somewhere rather more claustrophobic. It isn't always easy from these walk-through videos though to get a clear perspective of size, design and distances. I'd like to think this particular video perhaps doesn't do the final results justice.