Thanks for that!
Having said that, if they're like some of the people at the Bangladesh High Commission in London, you'll need to make sure that every single item of documentation they ask for is present, and 100% in order. While I was there last time (2003), several people got turned away for insufficient documentation, including a person dealing with the applications for journos and broadcasting staff who were going there to cover the cricket.
Personally, I think I'd still be inclined to get my visa in advance, because I'd rather be turned away from the BHC in London than put back on a plane in Dhaka!
On the other hand, this will be useful for people who do the trip regularly and know exactly what documents to bring. Sounds cheaper, too!