Bangladesh as a team aren't a bad side. In certain conditions, they can be a useful side, as seen in the fact that they took England to a fifth day in three consecutive tests. However, in each of those tests, Tamim made runs. In this game, Tamim has made runs, but noone else has. Tamim is super-awesome, and would play for anyone else in the world. However, no other Bangladeshi player would get in any other team in the world. Kayes is barely a county player and the attack of Shahadat and Shafiul would struggle to get me out. There are some 'useful' players; Mahmudullah isn't a bad number eight, Musfiqur Rahim is a good keeper and handy batsman, and cap'n Shakib gets Pietersen out for fun.
But no Bangladeshi player (Tamim aside) is really that good. Yes, there have been signs of improvement, seen in the elongation of games, but at no stage in any of the four tests have Bangladesh even looked like drawing. An exercise in futility underestimates the pointlessness of England playing against Bangladesh. The fact that England couldn't even be bothered to play two middling players in Broad and Collingwood doesn't suggest that the two seriesettes have been the 'ultimate test' (which test cricket should be).
I want to put it out there - I like Bangladesh. I like Tamim's swashbuckling style, where he can smash the hardest ball into row Z, and swish and miss the simplest half-volley; I like Shakib's plucky captaincy, where he randomly places fielders in positions where the ball never hopes to go; I like the fact that they field three spinners who don't even attempt to turn the ball. As patronising as it may sound, I like the underdog. So ultimately, I want what's best for Bangladesh, and what I feel is best for them is to play in a second tier of test cricket. Playing against Holland, Kenya, Ireland et al would give their players valuable experience of first-class cricket, rather than learning on the job (which they are forced to now). Tamim has played as many tests as other first class games, and cap'n Shakib has only played 45 first-class games. No wonder he has no idea how to position a field. By comparison, his adversary in Bangladesh, Alastair Cook, has played over 50 tests, but on top of that, over 120 FC games.
The infrastructure of Bangladeshi cricket is what it is, and while there are over 150,000,000 people (well over double the number eligible for England - not including South Africa), clearly there is not the level of youth development and scouting as there is in England or Australia. So the only way of improving Bangladeshi cricket must be allowing them to compete and develop against a more appropriate opposition. Surely the only thing gained from the tour of England (on a test level) was the realisation that Tamim was a world class player. They haven't really found out more about the respective talents or abilities of the rest of their team, as their team couldn't compete against England.
England clearly don't think it to be worth their while playing against Bangladesh for the foreseeable future, as no tour has been arranged for the next decade. How long before Bangladesh are cast into the international wildnerness by other countries who follow the same path? Bangladesh have improved, and they will improve in the future. But they'll need to raise their levels of performance even higher, even quicker, if there's going to be any point in teams like England playing them anytime soon. Which means it's vital that they play against likeminded countries; as a big fish in a small pond, if they are to gain the much needed experience to compete in the international arena.