The only thing that confuses me about bangladesh is, it is an Islamic country whose identity is based on a hindu language and it's history.
Off topic:
Bangla/Bengali is as much a Hindu language as much as Malay or Bahasa Indonesia is, in other words, although the origin is Sangskrit and Pali, it has transformed along the way. Majority Bangla speakers are Muslim. About 170 million (145 in Bangladesh, including diaspora and 25 in India) out of a total of about 250 milllion Bengali speakers are Muslims, that is about 65-70%.
Also Bengal was under Muslim Turkic Sultans since 1200 AD before Mughal took over in about 1600 AD. The East India Company took over Bengal in 1757. So for the last 800 years ethnogenesis of Muslim Bengali people is very much related to Islam and Islamic world expanded by Persianized Turkic and Turko-Mongol peoples, of which it was a frontier border region. I would recommend reading this book about Islamization of Bengal:
The Rise of Islam and the Bengal Frontier, 1204
Bengali language retained its own script due to decision of early Turkic Sultan's who chose this route for practical reasons. But script for languages are changeable. Examples:
Turkey: Arabic -> Latin (Turkified)
Central Asia: Arabic -> Cyrillic
Uighur: Arabic -> English -> Arabic
Korean: Chinese -> Hangul
Vietnamese: Chinese based Chur-nom -> Latin/Portuguese (Vietnamized)
Tagalog: Baybayin -> Latin (Spanish influence)
Malay -> pallava/Tamil -> kawi -> jawi (arabic based) -> Latin/(Dutch influence for Indonesia and British influence for Malaysia, Brunei and Singapore)
Usually a spoken language is a living language, the written script can be changed without a huge effort. To prove this point, all of us can easily and naturally write a spoken language using another script. Examples:
English: My name is kalu_miah
Bengali: Amar nam kalu_miah
Hindi: Mērā nāma kalu_miah hai
Chinese: Wǒ de míngzì shì kalu_miah
Korean: Nae ireum eun karu_miah imnida
Japanese: Watashino nam aeha karu_miah desu
Vietnamese: Tên của tôi là kalu_miah
Russian: Menya zovut kalu_miah
Malay: Nama saya adalah kalu_miah
Indonesian: Nama saya kalu_miah
Turkish: Benim adım kalu_miah olduğunu
It might be an interesting idea to develop a Latin version of Bangla script, not to replace the original Bangla script, but as a supplement, specially for computer users and expats, who understand the spoken language, but not the written script.