Currently I have two 1.6 MJs both 2010, I also have a Vauxhall Combo 1.3MJ (badge engineered Doblo), I much prefer the power of the 1.6MJs and also the six speed gearboxes. One of the 1.6s is a Maxi Van, the other is a sort of Combo with the seats in the rear and windows in the doors, in fairness I bought that one cheap for spares and it has already paid for it's self.
I can't comment re the later petrol versions as I prefer the economy of the 1.6 diesels and the pulling power on hills compared with petrol or the 1.3 MJ diesel.
I would have thought the 1.4 non turbo petrol,if it comes with a six speed box should give enough power and yet quieter motorway running in sixth gear when required.
I expect others on Forum will be able to give more specific advice on the petrol versions.

I would say if your current one is the 1868cc non turbo Doblo with the Lucas Epic injector pump, I had one of those in a 2003 Doblo van and found it to be much less powerful and also poor on fuel economy when compared with the petrol Peugeot Partner 1.6 I had replaced it with, so the next one I got was a 2005 1.9JTD 7 seater Doblo and even with over 220,000 miles it had plenty of power and was good on fuel, it only broke down once and that was a crank shaft position sensor, once it cooled down ten minutes later I was able to complete my journey home, diagnose the fault and fit new sensor.