Although the single X ballscrew, gantry side plates and overhanging Y axis (due to ballscrew position ) will reduce stiffness and performance my experiences of this type of design is that it is no problem for wood and plastic and will cut them all day long. If that is the intended use the I see no great issues on the mechanical side
Occasional aluminium plate is ok but for serious aluminium work this is not the machine to use and you need something stiffer in design including profile rails on most/all axes