Hm, interesting points, but let's consider the following*:
1.) The tempo game in Vintage isn't as massive as that of Legacy, hence why Vintage tends to be more cautious about plays and have greedier mana bases than Legacy. At least, this is what I've noticed as a Vintage player trying to get into Legacy.
2.) I think this is something we need to reconsider, because while those cards are good in other formats, they aren't good in Vintage. Trying to port Legacy Survival into Vintage is probably the worst way of doing things, as the two formats are vastly different. Just look at the Goblins deck, whereas Goblin Ringleader is good in Legacy, it's pretty bad in Vintage and Earwig Squad is fantastic.
That being said, what if we ditched all the permutation of the Legacy format and considered them in terms of Vintage. In Legacy it's fine bringing Vengevines into Rootwallas, but in Vintage wouldn't it be better getting Anger -> Battle Sphere -> Welder, seeing as not only do you have access to Tinker but also Moxen which make that plan far superior to the Legacy plan? Not only that but Welder -> Earwig Squad is brutal in Vintage against some decks, while not being that great in Legacy. Also, something like Big Game Hunter does kill a Lodestone pretty well, while replacing itself with an Ingot Chewer, or it kills a goyf/3rd Merfolk Lord.
As a whole, I don't think Vintage Survival would look like that of Legacy Survival, but rather it would be its own weird entity, less worried about the card advantage Survival can generate and more worried about the permutation it offers.
3 and 4.) Yes, but it also does things in Vintage it can't do in Legacy. The Welder plan doesn't really work in Legacy because you'd have to run artifacts that take you off the plan, while the Moxen help you accelerate into Survival and enable Welder. More so, Anger+Welder does stop things such as Blightsteel, which aren't really a factor in Legacy. Not only that but Legacy does tend to have a much more horizontal deck construction as the power level is lower, whereas Vintage has a much higher power level and as such requires more targeted answers, as seen in Earwig Squad being so much better.
Another interesting aspect is the popularity of Restoration Angel in Vintage, whereas it doesn't see much play in Legacy. The card is good with Survival but more importantly it shows the benefit of rebuying creatures, and as I mentioned before things like Abrupt Decay are becoming more popular. Now imagine being able to respond to something like a Lightning Bolt on your attacking creature by using Survival to get a Ninja of the Deep Hour, to rebuy your guy, draw a card, and either dodge removal or put more damage across. Sure it's a one time thing, but it's a lot of value for 1UG in Vintage. Especially if you rebuy something like Big Game Hunter against a Shop deck, assuring they can't depend on a Lodestone Golem in the near future without providing you with card advantage. Even just rebuying the one of Trinket Mage after drawing a Time Vault might be good enough in its own little way.
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I mean I love Survival as a card, way back when I played Legacy I ran Welder Survival, and honestly I think it might be nearing the time where Survival does have a place in Vintage, but it won't be in the Rootwalla or Retainers tricks we saw in Legacy, but rather in a new form that is unique to Vintage... After all, we've seen quite a lot of decks spring up this year that we didn't consider in the past from Affinity Shops to Blue Angels, and everything in between. Even if Survival isn't ready for Vintage just yet, I think it's vital for us to constantly keep on eye on it, as there's a chance that it might explode at any given time, with both the commander products and new sets coming out.
I also think that survival is a pretty solid card and could achieve some success (although it's probably slow). The problem is that for 1G, you have oath. Yes, cage exists, but outside that, you usually would prefer oath to sotf.
If I had to design a sotf deck, I'll probably start with 4 deathrite shaman and probably birds of paradise over noble hierarch. Then kataki, tarmogoyf, magus of the moon, thalia, viridian shaman, revoker, ooze... there are lots of options, and it should established if the deck is intended to control proactively or reactively. Or even combish!
Oath is a cool card, but I don't think it's comparable. Oath wants to win off running less creatures and results in combo or combo-control, while Survival wants more creatures and is more tool boxy. Also, being able to fetch an Earwig Squad off Survival against Oath would be devastating as it would take away all of their guys. Survival is the hybrid of Oath and BUG Fish, that doesn't really function as either deck alone. Earwig Squad also functions very well with Welder which is pretty good with Survival in Vintage, and not only that but Tin-Street Hooligan isn't terrible either when you consider the deck, since a lot of the time he can Stone Rain or stop certain combos, while enabling the Squad... I wonder how many people you could catch off guard by getting a Hooligan, killing their artifact and then playing out a Squad the next turn... Possibly even Ninjutsu-ing the Hooligan back into hand to do more stuff later.
See, this is why I love Survival so much, it's such a complicated card that can be built in many ways, and honestly I can't really figure out a perfect combination of cards to make it function the way I'd think, but I truly feel like there's something we're missing about it, because we're looking at similar but non-comparable cards like Oath.
Edit: Also the one of Yixilid Jailer becomes a lot better.