Well, I for one like the idea that has been proposed, otherwise I'd not have posted thoughts on it.
To the Master Rule question, I think the only real answer is to play in Master Rule 5. Not only do we have casual players who didn't keep up with everything here, to whom the new rule caters to, but we'll likely not start playing until April 1st rolls around, so we'd not be up to date with the rules if we went with MR4. But the main thing here is that people who exclusively want to use older summon mechanics such as Synchro, Fusion and kinda Xyz will be happy with the new rules, and anyone wanting to use a Link-centered strategy will be able to do so. It's just the most handy solution, in my opinion. I mean, I don't see us spamming out many Extra Deck bosses at once in the near future, and by the time we do, everyone will probably be used to MR5, and those who don't actually play enough to get used to anything can just skip links and play as they used to...
Speed Spells seem more like a hinderance than anything. But that's coming from someone who never watched 5ds. Allow me a question - So they're driving around in their D-Wheel, on a racetrack, yes? What's the point of going fast or having a super good bike (I know Yusei builds one up to a point, don't ask me how), if you only gain counters by game mechanics, you only need them to activate cards in the game, and how fast you go only matters because you get to go first if you're first on corner 1. To me it seems like all that matters is who accellerates the quickest, so they can go first, while everything else makes the bikes seem so useless. Please enlighten me.