Grouse has been pushing SEB products from the beginning they opened. I just think SEB doesn't have a temperature stable enzyme like Termamyl. Perhaps Grouse just does the best they can with their supplier's products. I have done step mashes, decoction mashes, and long rests. The best I every got with the previous processes I can get easier with Termamyl. I get better consistency batch to batch and shorter brew days. Unless someone shows that what we are doing generates off flavors compared to the other processes, Grouse is behind the times.
If you have a proper mash tun, then vorlauf is definitely beneficial for a clear wart going into the fermenter. If you brew using a bag, then vorlauf is not really possible. It goes into the fermenter with more sediment, but it clears up just fine. Don't know if a clearer starting wart has a noticeable impact on flavor. If you can do it with your rig, definitely vorlauf.
Palmer's book talks about the benefits of step mashes. I experimented with multiple step mashes even to the extent first put out by Andrew Laverly and did not notice a huge flavor benefit. Doesn't mean it wasn't there, I just couldn't tell as there were other factors that were much more dominating. If you are using something like the Grainfather that allows for easy step mashes, then go for it, otherwise I don't think it is worth the extra effort.