^ Oakwood bus runs on 7-min headways at the best of times, it cannot have any noticeable effect on the general traffic on Eglinton.
If the goal is to have two left-turn lanes from eastbound Eglinton to Allen, then the easiest thing to do is to designate two lanes for that purpose, and have the leftmost lane used by both the general traffic and the buses (Oakwood bus, Marlee bus, and the Eglinton surface bus if it still runs). With the proper coordination of traffic lights, cars turning to Allen will have same green phase as buses turning to the subway bays, and they will never block each other.
If routes 63 and 109 were combined, then Oakwood bus riders who wish to transfer to the subway would have to spend additional 8 min on the bus going up Marlee to reach Lawrence west, and then most of them (going south) would spend extra 3 min on the subway going back to Eglinton West. IMO, this is not a good idea.