I think it's quite... premature to say that a Nenshi-led NDP would have the upper hand in any election,
Historically speaking, the provincial PCs were typically Calgary centric and had substantial Calgary influence, this and the last UCP governments may as well be named the "United Calgary Party", and now we are talking about having an NDP leader from Calgary so that the NDP can have more influence and sway provincially?
Why don't we just pack up the legislature and move it down highway 2 Calgary. We can even pay for it with our own money given that Edmontonians are also funding their new arena through provincial tax.
How did Edmonton become such a limp wet noodle in the world of politics and power?
It's less about the city having political power and how the power balance in the province is distributed right now.
Rural Alberta is unlikely to shift dramatically towards the NDP, Edmonton is an NDP stronghold and Calgary is becoming more and more a swing area.
Because rural Alberta is disproportionately represented in the Legislature doesn't leave room for any strategy that doesn't involve strengthening the NDP's position in Calgary, if we want Edmonton to have any political leverage whatsoever. It's either that or something crazy happens and they lose all, or most, of their seats here.
Also, apart from Notley, Edmonton hasn't really produced many strong political leaders with provincial aspirations lately, save for MAYBE Iverson. Whether this is cause or consequence of the aforementioned balance of power is debatable, but doesn't change the reality of the matter.
A successful NDP government, regardless of who the leader is, and where he/she/they is from, will likely help redistribute this power and shift it back towards a more equitable position between Edmonton and Calgary, but that could take a while to happen.
Also, power is not only vested in the Premier, but their base and by extension, their cabinets, which will likely figure a LOT of Edmontonians in an NDP government, even if the Premier is not from here. Edmonton is their stronghold, and they would do well to keep their voters here appeased, but for any of this to happen, we need to flip votes in Calgary.
Add to that the fact that the "rivalry" between the cities is felt much more strongly on their side of it than ours, and they're a lot less likely to vote for an Edmontonian Premier than the opposite, and the best strategy starts to get clear.
I would love to have an Edmontonian as Premier, or even an NDP leader from a smaller city that doesn't have closer ties to either city, and these might happen if the UCP is dislodged from power, but I don't really see it happening right now. The federal NDP does have a person who could possibly make it happen in Heather McPherson, but I doubt she'd leave her very safe MP position to gamble her political career in an attempted shot at premiership. Other than her, I don't see a name that is strong enough to make this happen, while there are a few names in Calgary that could potentially kickstart the process, Nenshi being the strongest one, IMO.
As people said here already, he has good acceptance here, has never been politically aligned before, was a very competent mayor and is still a popular guy down in Calgary.
Our closest name in terms of strenght, Iverson, has been linked to the Liberal Party through most of his career (a big no-no even in Edmonton, but more so in Calgary and rural Alberta), and hasn't had the same level of success and popularity as Nenshi as mayor.
If anything, by NOT considering a Calgary leader for the NDP, that can turn votes there and dislodge the United Calgary Party, We might then want to do everything that you said, because we'll be keeping 100% of the provincial political influence in the hands of Calgary and rural Alberta.