Well the new rule about having an extra (5th) fielder outside the circle in the last 10 overs has helped I think. For example in our last match vs NZ, NZ only managed 53-4 in the final 10 overs with Ross Taylor out in the middle the entire time. That would not have been possible in the old rules.
That being said, I think batsmen have just gotten too good these days. The sheer number of ramps and dilscoops and the success rate of them indicates as much. It will be interesting to see if any bowlers can keep an econ rate under 5 in the champions trophy. That would prove that it can still be done.
And yes our ODI side needs 2 things in my opinion to be a side without weakness.
1) a genuine power hitter
2) a wrist spinner capable of destroying the opposition like Rashid Khan
I hope we can find at least one of those by teh 2019 world cup.
In the absence of a real power hitter, we have to rely on our top order to finesse their way to a big score and hope that 2-3 batsmen remain for the final 10 overs. Thats the only way you can attempt to score 350 and compete with the Englands, Australias, and South Africas who have power hitters.