Heres a breakdown of some evidence I gathered:
I did a count and in all the volumes covers, Alibaba and Aladdin were equally featured on the covers with a count of 10 times.
Breakdown of protagonist in each arc:
Chapter 1: Aladdin
Dungeon Arc: Alibaba
Kouga Clan Arc: Aladdin
Morgiana Slave Arc: Morgiana
Balbadd Arc: Alibaba
Sindria Arc: Alibaba
Zagan Arc: Hakryuu/Aladdin/Alibaba
Sindria 2 Arc: Aladdin
Pirates Arc: Aladdin
World Exploration Arc: Aladdin/Alibaba/Morg./Hakryuu
Magnostadd Arc: Aladdin
Balbadd 2 Arc: Alibaba
Alma Torran Arc: Alibaba/Aladdin
Kou Empire Arc: Hakryuu
Final Arc: Alibaba
Overall, they both are practically equal in terms of POV of the story, it’s like 2 sides of the same coin.