During slow times it could work nicely. I don't see why it wouldn't. If there are any headliners available for same day bookings you should be able to grab those as your extra FP. Doing TT at rope drop isn't exactly speedy these days, with a slow line to begin with and FP cutting in right at 9. You could then go ride either TT or Soarin' after your "throwaway ride" giving you multiple rides on one of them.
Works even better for booking a FP at another park, by using up your useless one you can then replace it with something useful that you couldn't ride at RD from another park.
This logic doesn't quite make sense.
Current status: 17,000 Soarin FP and 13,000 TT FP to go to 40,000 guests. Clearly insufficient supply.
Guest: Can I just have 2 FP to Soarin and/or TT? I'll be happy then.
Answer: No. There is not enough to give 2 to each guest. Do the math. There is not enough to give even one to each guest.
Survey: Ok, but what if I go on Figment first. Then can I have a second FP to TT or Soarin?
Well obviously the capacity has not changed at all. This makes absolutely no sense that Disney is going to say "Okay folks, as long as you use a
throwaway fastpass first, we'll give you a 2nd.
You might as well say "As long as you run 2 laps around the park first" or "As long as you'll do some other random task first".
None of this changes the capacity of Soarin and TT. Thus none of this changes whether you can truly give each guest 2 FPs to these rides. THey may make some sort of incentive to burn your FPs sooner to get a bit of whatever is left over, but given the capacity numbers, by the time this comes to be, anything you might want will not be available. Because we fall right back to, 40,000 guests already queued up nearly all of the 13,000 TT slots from home, months ago.
Maybe you'd luck into one by spending your first half hour riding Figment, but you could also just use your first half hour riding TT and not bother w the gamble.
Unless you change the supply of TT and Soarin, you cannot give each guest 2. The numbers aren't there. I'm all for TT being doubled in capacity or having a 3rd thrill ride at Epcot... but that is the ONLY solution that will lead to increasing the capacity of the two desirable rides there. The problem at Epcot is not the FP+. It is the lack of capacity on its desirable rides.