My take too. I'm working under the assumption that ALL current drones are going to enter the Legacy classification at some point and I'm possibly going to need to replace my
M2P as a result, but until this is 100% finalised there is still some wiggle room as to exactly what that will mean in terms of restrictions and when it will come into force. There is also a possibility that the CAA might decide that given models - especially the more popular ones like DJI's - might be grandfathered into one of the classifications without the necessary marking, although they are certainly not obliged to do this as the law is current written.
What I'm not clear on is whether or not it's even possible for a drone to get the classification mark yet, either in the UK or the EU; AFAIK, no drone currently on the market has one, and I'm not sure that if a new drone were to be released tomorrow it would be able to ship with one either. I can't imagine that manufacturers are going to be particularly keen on releasing newer models of higher-end drones without one given that clueful buyers are unlikely to want an aircraft that will become Legacy less than a year after purchase. Some more clarity on this (and some product annoucements!) would be just as welcome as updates to the operational requirements, IMHO.