Grandvalira Canillo, Soldeu, El Tarter and Encamp have a larger percentage of blue and green runs than Pas de la Casa / Grau Roig for example which have a larger percentage of reds and blacks, so you are correct they are probably better areas for complete beginners, however that said there is still a good selection of blue runs in Pas de la Casa / Grau Roig and there are two beginner areas in Pas de la Casa also. I do not think you will find it an issue as there are many beginners in Pas de la casa as well as more experienced skiers and snowboarders, generally it is a good all round resort with an excellent ski / snowboard school.
we are two snowboard beginners which means that we will do mostly blue slopes.
is it true that the area of canillo and el-tarter have more to offer for beginners than the area of pas de la casa ?