Ok, good point I didn't really think about the funding which is really stupid on my part. The thing is I don't want to initially charge people to play as they'll just think it's a scam so in terms of the funding I was thinking of letting people play for 1-2 weeks with full gear and the queues; getting feedback and then implementing a payment method.
From what I know a lot of people did love s15, many old players came back for it and from what I know it did not recieve too much criticism apart from rage at symbiosis (ferals having disp. lol), thundercleaves randomly globalling people and that was about it as far as I remember. Please post any more complaints about the season if you can would be interesting.
I would also consider wrath s8 but I feel in the current state of PVP more people would be inclined to go back to MoP for some fun queueing as it's more familiar than wrath, idk though.