I suggest you spend a breakfast al fresco at the Three Mills Cafe and observe bahaviour, and also look at satellite/aerial views from Bing and Google.
1) TfL's OWN FIGURES show that 60% of cyclists were using the flyover when they planned this inherently unsafe facility. My own breakfast sessions at TMC suggest the figure is closer to 70%.
2) one Westbound traffic lane on the flyover is permanently closed, and during 2012 Olympics one Eastrbound lane was also closed. Gridlock/sky falling down etc did not materialise on the flyover. If anything I saw some moments when the only vehicles moving on the flyover were bicycles
3) from the Google & Bing images i'd estimate that 80-90% of the motorised traffic in the East-West corridor is going to or from the roundabout to join or leave the A12. Very little cycle traffic is likely to do this because immediately North of the roundabout this becomes the A12(M) M11 Link Road, and immediately South it is a fast (40/50mph) 6 lane dual carriageway feeding the Blackwall Tunnel.
4) the whole roundabout system is a giant bodged job, as the East side slip roads carry 2-way traffic, and have a messy set of cut-across links. This means that on the NE corner there is a set of traffic signals to let traffic out from Marsh Gate Lane,which regulate the flow on to Stratford High Street. On the SE corner there is a wide build-out island that stops mad drivers driving head on into traffic coming Eastbound to get to the various premises and Hunt's Lane. With the traffic queues at busy times extending well past this protected crossing point the less confident cyclists, dismount and cross between the stationary motor vehicles, at other times they wait for a gap to cross the single traffic lane. Westbound a similar detail applies - the queu back from the roundabout is usually stalled well past the foot of the flyover ramp, and the pedestrian lights to the West of the Church can be used as a regulating detail to stop the traffic and give the opportunity to cross to or from the flyover.
5) CS2 on the roundabout is inherently dangerous, as 100% oif the motor traffic (with the exception of the through bus services) WILL drive directly through the path of 100% of the cyclists using CS2 - ie the hazard is delivered for 100% of users. The only management of this risk is through the use of traffic signals and road signage, and reliant entirely on the human factor of user compliance with the instructions given. this was flawed in the first design, and it is even MORE dangerous in the second design.
6) The very fact that TfL finds it necessary to produce a video animation to show how to use the facility condemns it as unfit for purpose - by definition good road signage should be quickly understood and easily complied with by any road user coming across it for the first time. the traffic signals for cyclists are dangerously ambiguous - first you are expected to stop[ where a red bicycle symbol is illuminated alongside a green standard signal. When the standard signal shows a red light and a green cycle symbol is illumionated you are expected to move forward BUT THEN you are expected to stop at the next standard red signal - having been instructed to pass an identical red signal barely 20 metres earlier. The timings for this are such that a cyclist who misinterprets this confusing information can ride out into the path of traffic going around the roundabout just as the traffic signals for this turn green. The whole system breaks down when, with a gridlocked roundabout motor vehicles get 'trapped' in the reservoir between the split traffic signals and the second set at the roundabout.
7) for cyclists riding over the flyover the hazard of a motor vehicle driver turning left or driving through their path are..... go on have a guess.... 0% Nil zilch, aside from any suicidal driver who wants to drive over a 7 metre drop on to the roundabout below.
TfL engineers did design a scheme to use the flyover. If it had been done this way, then we would very probably saved 3 lives in the past 2 years. Someone or some reason allowed this fatally flawed design to be delivered instead. At Brian Dorling's inquest we had the hint, and the potential to ask a hugely embarassing question - if TfL KNEW that 60% of cyclists were using the flyover and that so little motor traffic was using it that one lane on each carriageway could be converted in to a split walking and cycling route, why did they use the roundabout route?
Plus the key detail on the roundabout 100% of motor traffic drives straight through CS2 at least once but on the flyover 0% of traffic is going to do this.
We sadly have another inquest to be held. Let that question be asked.