A lot of other options were recommended by the Leveson Review, and even more are being tried out like Fast Track Courts for the simpler cases that would likely get swept up in this. That the recommendation focused on by the government and even more by the media is reducing trials by juries is telling.
Also, the reason given for this recommendation isn't that'll save money - it's to cut the backlog. It's about victims, witnesses, and defendants waiting 2-4 years for trials.
Juries aren't the main cause of the backlog. It's the lack of court rooms (Tories closed a lot of court houses), lack of judges, and lack of barristers (which is why recommendations include the Government adopts a matched pupillage scheme). Even increasing sitting days, as has happened, isn't going to work without those. It's also the lack of court staff to get all this done, to the point that there is discussion in some regions to redefine 'non-mobile grade' to mean 'we can make you move for business reasons for X days a year.'.
It isn’t a mix of people though. Retired people and students are usually over represented because lots of working people defer, appeal to be released etc.
Working isn't a reason to get out of jury service, and the most common reason I've seen to appeal to be released has been ill health - more common with retirees.
While the news often reports that it's to be before just a judge, the recommendation is for some either-or offences to be heard by judge with two magistrates, as already done for appeals. Magistrates are all volunteers, far more of them are retirees compared to jurors, and we have a national shortage of magistrates just as we have of barristers and judges.
Magistrates also generally booked for one day at a time, at least at Crown Court where they're usually in one day a week max IME- if we're going to be having them on multi-day trials, yeah, it's probably going to be all retirees because while they are committed to 13-30 days a year (the recommendation is for Crown Courts to sit 113k days a year), unlike jurors they can't be compelled so Magistrates who work are less likely to take multiple days off. Magistrates can stop at any point since they're volunteers.
Anything that can be said about quality of jurors can also be said about judges, barristers who can sit as Recorders, and those magistrates. If you want to see biased, jaded opinions, someone who has sat on a few dozen rape trials is a strong candidate.
I've worked with a lot of juries and judiciary, and I'll lean towards juries.