My thinking is partitions why not if you cannot do without them.
It is possible to have only some of the CA PPM objects partitions. However, once an object is partitioned all instances have to be partitioned and firstly there has to be a partition model created.
Templates can be associated with OBS units (departments) and OBS view rights will determine who can see which.
If you do not have partitions all instances of and object will have all the attributes, but you can set different views depending on the object or resource association to an OBS unit (or group membership). In addition to securing the views with different attributes you can use display conditions.
"showing different values in 2-3 existing attributes" is not clear. Typically each instance can have a different value for any attribute, though in some case the value can be the same. Like default layout, scheduler format etc.
To me those things only do not sound like enough justification for the overhead and administration of partitions.