The majority of developed countries consider hiring foreign workers to be a valuable part of their workforce.
Most developed nations consider foreign workers to be an asset to their workforce.
takashiさんの英文は次のように言うと、より自然な感じになりますよ。
ーThe majority of developed countries consider hiring foreign workers to be a valuable part of their workforce.
または次のような言い方もできます。
ーMost developed nations consider foreign workers to be an asset to their workforce.
「先進国の多くは、外国人労働者を貴重な労働力と考えます」
ご参考まで!