Wait and see for me.
We're up at 7 am anyway getting ready (or already waiting) for RD and/or getting ROTR BGs, etc. So the 7 am opening for reserving the first LL time isn't a deal breaker for me.
For trips that are just my wife and me, I could see paying an extra $30 for MK and DHS as long as
Genie+ actually results in us getting to use the LL line for a sufficient number of rides throughout the day. If it's only a handful, not worth the cost... we'll just wait in SB for those few additional rides since we'd be in SB for the rest of them anyway.
When traveling with extended family, it complicates matters because our traveling partners may not want to spend the extra and we wouldn't want to pressure them just so WE don't have to wait in lines (even if I'm generous and offer to pay for everyone, now we're talking about a significant chunk of change... not to mention that most of my family would not want to take "charity" so they would feel more obligated to spend out for it themselves).
As of now, we're still planning to be in MK on 1 OCT (no other park days for this trip). If they do roll out G+ before then, I'll volunteer to spend $30 in order to be a guinea pig for the rest of you and let you know what our experience was.
I enjoy Space Mountain and 7DMT, but they aren't "must do's" for us. Sometimes we skip them even if the line is reasonable. I would not pay extra for them (even if only $5 pp). So the additional cost for MK (for the two of us) would not exceed $30. At least until Tron opens. I might pay extra for that, but the more likely scenario would be that I would just wait an hour in SB for it. If the line exceeds an hour, I'd be tempted to pay extra for LL (IAS), but not an insane amount like $20+ (probably not willing to ever spend more than $10 per person for any one ride). So I might get shut out of that one or just have to wait for 2-3 hours.
At DHS, I would attempt to get a ROTR BG first and if unsuccessful, would be tempted to pay for LL (IAS) to ride it. But again, that would depend on the price tag. As much as I love that ride, I just don't think I can bring myself to fork over $50 for a single ride. If G+ will get us access to ToT, MFSR, SDD, TSMM, Star Tours, and MMRR (?) through the LL, there might be adequate value to use it at DHS for us with the $30 price tag. The real question is how much will ROTR cost and will I break down and pay it if I don't get a BG?
For AK, I would be inclined to just use SB for the Safari, EE, Dinosaur, etc. If FOP costs $15 as an IAS to use LL, it's still $30 for the day for the two of us. Even if it's more than $15 due to "surge" pricing, it would be slightly more stomach-able (is that a word?) since it would be the only extra ride cost for the day.
Similarly, for EPCOT we probably would just use SB for the rides (skipping TT and Frozen if they're over an hour wait). We've ridden Remy at DLP and it's a great ride, but I doubt I would pay extra for it. I would try to get a VQ (BG) for it but, if not successful, would probably skip it until a future trip. That being said, since we didn't pay the extra $15 each for G+ that day, we could instead spend that much for IAS to ride Remy using the LL and still be staying within that $30 per day price range.
Don't get me wrong... I think it absolutely STINKS that everyone will now have to pay extra to skip some of the SB lines (especially for families/large groups where it will add up). But if the $15 per day for G+ gets us enough rides using the LL, I think we could make it work for the two of us by purchasing it only at MK and DHS. We could then budget that $30 for AK and EP days to ride FOP and either Remy, Soarin' or TT (depending on the cost as well as free BG availability).
My perspective about this is probably shaped largely by the fact that I have been going to WDW since 1975. We used the ticket books back then and there were no FPs. You waited in line (often for an hour or more). I've experienced every variation of prices/line options.
I've been to WDW when they had:
Ticket books to ride the rides
All-inclusive rides but no FP existed
Legacy (paper) FP
FP+
Socially distanced SB only during COVID
...and now G+/LL/IAS
Bottom line... the price of WDW went up by $15 per day if we want to avoid having to wait in SB for all rides. I don't like the extra cost one bit, but whether I judge G+/LL to be a failure or not will depend on how effective it is in reducing the waits for that price.