The class system I see as overall being a good thing; in PS giving one player too many options turned people into one man armies being able to take down infantry and vehicles well and then heal, repair and use command abilities all with a single load out.
Making players specialise to a specific role at a time will lead to a great amount of teamwork being required, just like in the early days of PS where people were restricted with their certs (imagine a time when only a few people were BR15, let alone 20) and so had to specialise totally.
In my upgrade projects
certification overhaul I retained the inventory and cert system, just massively reduced the amount of cert points available so that any one player could only really afford one advanced weapon cert (eg HA or AV), a support role and a vehicle as well as a special armour (MAX, Agile with jump jets or Infil).
However the problem I see is one of specialised squads of players. For example if you have a fast assault squad equipped with jump jets to perform hit and run attacks, will any of them be able to have a support role, or will they be confined to that fast assault role while they use the jump jets? Will they be able to use AV or AA weapons (perhaps weaker, lighter ones than a Rexo may carry)?