Look we all would love to see the BAF flying the latest advanced birds, but the reality is we are first concentrating on building our economy and infrastructure. We have a very large armed forces for our tiny defence budget, over 300,000 active men under arms, a number larger then many western nations. All this on a budget that's less then 2% of our GDP, which means all the expense go to paying salaries and such, very little is left to buy expensive modern equipment.
But things will change in the very near future, our economy is expanding at a good rate, in fact our GDP will grow faster then indias this year and into 2014. As the economy expands, our ability to new advanced weapons gets easier.
Now speaking about the f7bgis, remember even india flies mig 21s still, and these "stop gap" birds are quite advanced for there price, MFD glass cockpit, advanced multi mode radar, double delta wings, BVR capability etc. Bangladesh will soon be able to afford j10s, su30s, or latest migs within the next 10 - 12 years when our GDP reaches $300bn, and the defence budget doubles to over $5bn.