Quisiera is a more polite and heartfelt way of saying "I want". It's a special form of the verb querer (to want) that translates to "I would like" or, more emotionally, "I wish."
In the song, the singer uses it to express a deep, almost dream-like longing: "Ya quisiera tenerte" (I wish I had you). This single word perfectly captures the central theme of wanting to be more than just friends, making it a beautiful and useful word for expressing your own desires.
Ever fallen for a friend and been too scared to say anything? That's exactly what's happening in Grupo Frontera's first original song, "Más Que Amigos."
The singer is in a tough spot. He and this person decided, "pensamos en sólo ser amigos" (we planned to just be friends), but that plan went out the window. Now he's confessing, "tus ojos me dejaron enamorar" (your eyes let me fall in love). He's terrified that if he tells her how he feels, she'll run away, and he pleads with her not to go even if she doesn't feel the same.
He's done with pretending. He lays it all out with the line, "Ya no quiero ser tu amigo, quiero ser mucho más" (I don't want to be your friend anymore, I want to be much more). He's tired of seeing her only in his dreams and wants a chance to prove his love. He's asking her to let him be a part of her world and show her how much he can love her. It's a classic, heartfelt plea to escape the friend zone.