Lets say half the B-D to Yonge transfers decide to stay on Eglinton and go over to Yonge. This effectively reduces the transfers from B-D to Yonge since it is split between 2 stations and not all at one. This means the dwell time at the Yonge-Bloor station would be less and more trains could run on the Yonge line. It may actually help relieve the Yonge line - although I doubt it would help to any degree in reality.
If the DRL were ever built to Eglinton, these riders would transfer onto the DRL - thus relieving the Yonge line of those riders and reducing the dwell time at both Yonge-Bloor and Yonge-Eglinton stations.
Something should run through at Kennedy - either the SRT or the Eglinton-Morningside-Malvern (or whatever its called). I would say it should be the one with the higher ridership.
If you say that the transfer is warrented because an SRT rider can get off and transfer to Eglinton LRT, GO, or B-D, then a similar thing should be done with GO. have GO stop at a Kennedy north platform. Riders can either switch to Eglinton LRT or B-D, or have a simple along-platform transfer to the new Kennedy south platform, where they can take the GO into Union. The advantage is that now you can have different headways on Eglinton LRT, Morningside LRT, B-D, GO north (GO train going between Kennedy and Stouffville) and GO south (GO train between Kennedy and Union).