I quite enjoyed the prerelease today, despite all the planeswalkers. I do run a few in my cube as well, but in general, I found that running too many doesn't make for fun gameplay. For me at least, some players did enjoy them to be fair. I've cut more and more planeswalkers from my cube, to the point that I now run only 7 (three of them require two colors, two of them require three colors), plus 4 flipwalkers, in a 450 cube. I like what those walkers bring in those numbers, but then again, your mileage may vary.
Some of the planeswalkers in War of the Spark, however, are pure gold. I think you should at least check out the uncommons with an open mind, since they can only tick down. They are more like living enchantments that any deck can kill than the value engines you're used to think of when you think of planeswalkers. They truly feel and play
wildly different from the planeswalkers we're all used to. I would encourage everyone to play a few games with
Saheeli, Sublime Artificer. Tell me that isn't one of the sweetest spells matter card ever!