For what it's worth, finding matches for turf is pretty easy at the moment. Sometimes you have to wait a bit longer, maybe time out and queue back in, but I'd say that getting actual matchmaking errors is much more rare than in newer games in the series. There's a bunch of downtime here and there though, and some features are a bit flaky. Considering the lousy quality of the NSO service on switch, I'd say it's pretty decent already, and it only keeps getting better.
On the other hand, ranked battles are pretty notorious for not having anyone to play when I want to give them a shot, so being able to play at all is quite rare, even when the NEX implementation used by Pretendo doesn't consider rank at all and throws random people into the game.
As for new accounts, from what I understand, it's totally possible to transfer over save data, and it's documented in the Pretendo setup guide, but it seems like plenty of people don't bother to scroll down to get to that part. In general, I don't get why people would be hesitant to mod their Wii U, as it's quite easy to do and vastly expands what Pretendo can do on top of a bunch of improvements that can be made to the experience. A straightforward Aroma setup is extremely easy to set up, and even results in homebrew popping up as standard icons on the home screen. It doesn't even come with any tools that enable piracy out of the box.
Also, I have a question to anyone here who might be already paying for Pretendo: how's the population of the beta servers? I've been actively considering paying for access, and maybe even taking a stab at doing a bit of development here and there, although my sights right now are on another project for the Wii U scene.