compare 2 tables with minus with a SDO Geometry shape column
I found that the only way to compare with RACDB + SDO_GEOMETRY row is to compose the SDO like this:

select tm.id,tm.nume_sit,tm.numar,tm.x,tm.y,
        MDSYS.SDO_GEOMETRY(2001,NULL,
                           MDSYS.SDO_POINT_TYPE(tm.x,tm.y,NULL),
                           NULL, NULL) as shape
from (
select pub.id,pub.nume_sit,cpu.numar,cpu.x,cpu.y from 
    SOL_PUBLIC.PUNCTE_PERIMETRU_SIT@RACDB cpu
    inner join SOL_PUBLIC.SOL_CHESTIONARE@RACDB PUB
        on cpu.FK_ID_CHESTIONAR=PUB.ID
minus
select prod.id,prod.nume_sit,cpr.numar,cpr.x,cpr.y from 
    SOL.PUNCTE_PERIMETRU_SIT cpr
    inner join SOL.SOL_CHESTIONARE PROD
        on cpr.FK_ID_CHESTIONAR=PROD.ID  
) tm
ORDER BY nume_sit,numar;


as for converting the SDO_GEOMETRY to text, if anyone need this, you have to do something like this:

to_char(substr(cpu.shape.get_wkt(),1,4000)) as shape