The highest dream we can see are:
For Test Series:
Bangladesh makes the series draw by playing the full series. (This is highest, anything more than that will be complete impossible)
For ODI Series: Bangladesh win at least one match and make the 3rd ODI important. (Some can expect to win the series)
T20: Bangladesh win the match (The dream cannot be more than that)
But from my side the same expectations that I personally had before T20 WC, which is FACT
“I hope Bangladeshi players will show professionalism on their Technical Standard (Batting, Bowling & Fielding), Game Planning and Attitude (or Body Language) that we observe in a Test Team”.