First of all forget about 1971. We are not grateful enough to remember about that all day long. Most of the Bangladeshis think its only them alone who brought freedom. We give little credit to India for their 13 days war or giving shelter to Bangladeshis.
Its totally a matter of Bangladeshis. They wanted freedom and there were many counties to help us. You and we both know that there were Indian interests to break pakistan and you fought for our cause. Also you got the reward.
But that doesnt mean we will be loyal for India for eternity keeping that in mind. Because its India and Indian hindutva people alienated Bangladesh by not giving proper share of water and land boundary. Also by pushing Indian Muslims to BD. And so on.
And you can have strong army but you are vulnerable from inside we know it. People of your country are discriminated. They want freedom. Thats why there are so much arms struggles. We Bangladeshis strongly feel freedom of all people. So are sympathetic to anyone who seek that.
Now keeping in mind BD you should forget about an invasion inside it because its another country. Not any state of yours where you always give them ill treatment. International affairs dont work like this. Bangladesh can be seen tiny with small economy with small army. But it has International ties. BD has 50 friendly Muslim countries, China, USA, Russia, EU. If you invade BD an anti Indian ally will be created automatically.
India cant ever dream of taking a country like BD with its army. Because it will be the end of present India from history.
BD is a different secular country unlike India and a moderated Muslim one.
Saying all this my last response to India with a middle finger,
"Hamara ek bal bhi na ukhar paye ga tu"