I'm not so much "die hard anti-sata" as I am "insistent on pointing out that it CAN be a risk" since the SATA power connector is NOT rated to handle the max power that can be drawn from the PCI-E bus and still be in spec on that bus.

I recognize that a lot of cards don't pull the full 75 watts (plus voltage conversion inefficiency) the PCI-E bus allows - but unless you can actually measure the power draw of YOUR cards at the settings YOU use, there is no way to be sure that you are staying within the 54 watt max power draw rating for the 12VDC connections on a SATA power connector.

Daisy chaining - depends on the specific power supply and cables, but most CABLES for SATA use are not designed to handle 100+ watts that 2 risers commonly pull, much less the over 150 watts they COULD possibly pull.
I've seen SOME SATA chains that don't use heavy enough wiring to handle 75 watts - and rare cases of MOLEX chains that have that light of wiring as well.

None of the risers I have examined use 5V input at all, much less 3.3V input - ALL of their power comes from the 12VDC lines - but I don't have any "pure SATA" or "pure MOLEX" risers to check, those in theory COULD be different.

Note that the PCI-E bus itself only supplies +12VDC and +3.3 VDC - if a SATA-based PCI-E riser used the 3.3v feed from the SATA connector, it wouldn't need any power conversion AT ALL and would only have probably 2 electrolytic caps on it AT MOST - one for 12VDC one for 3.3 VDC.
3.3 VDC on the PCI-E bus is also stated as "standby power", indicating that the load would be very small when it is used at all and that the power conversion circuitry on a riser probably doesn't eat even a watt.