If Bangladesh can beat Ireland. England can tie with India, Ireland can beat England, England can beat South Africa then this world cup is all about how pitch and condition are. No team looks to be dominating especially in Group B. Every team can win on their day.
Not really. I don't understand your point because ever since Aussie fell from their heights, no one team has ever really looked dominant in ODIs. Any team can beat any team on a given day - all of the top teams are pretty evenly matched. Ireland beating England was an upset, a hiccup by England. It's highly unlikely that the Irish will beat another team (aside from the Netherlands). Bangladesh are also not expected to beat anyone except the Irish and the Dutch. West Indies are also a weaker side than the top 3 - England, India, and South Africa. As far as the top 3 go, it's a toss up.
Same can be said about Group A - it's a toss up between Pakistan, Australia, and Sri Lanka on who wins on any given day when facing each other. New Zealand is the "West Indies-like" team where they're better than the minnows but not quite up to the mark to the top 3. And Zimbabwe can be compared to Bangladesh. Since the minnows haven't caused an early upset yet, it's showing the reality - the true dominant sides being on top.
Of course pitch conditions matter, but the teams that are able to adapt to the conditions will be able to do much better. This has always been true of cricket though.