Historically Monarch have never dropped cadets either until all of a sudden a few months ago it happens. "Historically" isn't necessarily the best thing to go on in aviation when things are changing. BAs recruitment needs have certainly changed in the past, and with short haul review coming up I'd say it's not a sure thing.
As for the risk of EZY reducing your hours/wage after 12 months? Pretty much nil chance. BALPA did very well to secure the NEC which guarantees you only spend a max of a year before being interviewed for permanent SO (with the vast majority passing the interview). Which is £40k+ first year at the moment.
That being said. Both schemes are the best choice a budding new pilot has. Pre-tagged is the least risky way forward these days.